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http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#BQN
|
BQN
|
•Out 1⌽∾˜18⥊•Repr"•Out 1⌽∾˜18⥊•Repr"
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Lasso
|
Lasso
|
push: queue->insert
pop: queue->get
empty: queue->size == 0
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Logo
|
Logo
|
make "fifo []
print empty? :fifo ; true
queue "fifo 1
queue "fifo 2
queue "fifo 3
show :fifo ; [1 2 3]
print dequeue "fifo ; 1
show :fifo ; [2 3]
print empty? :fifo ; false
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#JavaScript
|
JavaScript
|
// this just helps make partition read better
function swap(items, firstIndex, secondIndex) {
var temp = items[firstIndex];
items[firstIndex] = items[secondIndex];
items[secondIndex] = temp;
};
// many algorithms on this page violate
// the constraint that partition operates in place
function partition(array, from, to) {
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random
var pivotIndex = getRandomInt(from, to),
pivot = array[pivotIndex];
swap(array, pivotIndex, to);
pivotIndex = from;
for(var i = from; i <= to; i++) {
if(array[i] < pivot) {
swap(array, pivotIndex, i);
pivotIndex++;
}
};
swap(array, pivotIndex, to);
return pivotIndex;
};
// later versions of JS have TCO so this is safe
function quickselectRecursive(array, from, to, statistic) {
if(array.length === 0 || statistic > array.length - 1) {
return undefined;
};
var pivotIndex = partition(array, from, to);
if(pivotIndex === statistic) {
return array[pivotIndex];
} else if(pivotIndex < statistic) {
return quickselectRecursive(array, pivotIndex, to, statistic);
} else if(pivotIndex > statistic) {
return quickselectRecursive(array, from, pivotIndex, statistic);
}
};
function quickselectIterative(array, k) {
if(array.length === 0 || k > array.length - 1) {
return undefined;
};
var from = 0, to = array.length,
pivotIndex = partition(array, from, to);
while(pivotIndex !== k) {
pivotIndex = partition(array, from, to);
if(pivotIndex < k) {
from = pivotIndex;
} else if(pivotIndex > k) {
to = pivotIndex;
}
};
return array[pivotIndex];
};
KthElement = {
find: function(array, element) {
var k = element - 1;
return quickselectRecursive(array, 0, array.length, k);
// you can also try out the Iterative version
// return quickselectIterative(array, k);
}
}
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#FreeBASIC
|
FreeBASIC
|
' FB 1.05.0 Win64
Function formatRange (a() As Integer) As String
Dim lb As Integer = LBound(a)
Dim ub As Integer = UBound(a)
If ub = - 1 Then Return ""
If lb = ub Then Return Str(a(lb))
Dim rangeCount As Integer = 1
Dim range As String = Str(a(lb))
For i As Integer = lb + 1 To ub
If a(i) = a(i - 1) + 1 Then
rangeCount += 1
ElseIf rangeCount = 1 Then
range += "," + Str(a(i))
ElseIf rangeCount = 2 Then
rangeCount = 1
range += "," + Str(a(i-1)) + "," + Str(a(i))
Else
rangeCount = 1
range += "-" + Str(a(i-1)) + "," + Str(a(i))
End If
Next
If rangeCount = 2 Then
range += "," + Str(a(ub))
ElseIf rangeCount > 2 Then
range += "-" + Str(a(ub))
End If
Return range
End Function
Dim a(1 To 20) As Integer = {-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20}
Print formatRange(a())
Print
Dim b(1 To 33) As Integer => _
{ _
0, 1, 2, 4, 6, 7, 8, 11, 12, 14, _
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, _
25, 27, 28, 29, 30, 31, 32, 33, 35, 36, _
37, 38, 39 _
}
Print formatRange(b())
Print
Print "Press any key to continue"
Sleep
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#M2000_Interpreter
|
M2000 Interpreter
|
Module CheckIt {
Function StdDev (A()) {
\\ A() has a copy of values
N=Len(A())
if N<1 then Error "Empty Array"
M=Each(A())
k=0
\\ make sum, dev same type as A(k)
sum=A(k)-A(k)
dev=sum
\\ find mean
While M {
sum+=Array(M)
}
Mean=sum/N
\\ make a pointet to A()
P=A()
\\ subtruct from each item
P-=Mean
M=Each(P)
While M {
dev+=Array(M)*Array(M)
}
\\ as pointer to arrray
=(if(dev>0->Sqrt(dev/N), 0), Mean)
}
Function randomNormal {
\\ by default all numbers are double
\\ cos() get degrees
=1+Cos(360 * rnd) * Sqrt(-2 * Ln(rnd)) /2
}
\\ fill array calling randomNormal() for each item
Dim A(1000)<<randomNormal()
\\ we can pass a pointer to array and place it to stack of values
DisplayMeanAndStdDeviation(A()) ' mean ~ 1 std deviation ~0.5
\\ check M2000 rnd only
Dim B(1000)<<rnd
DisplayMeanAndStdDeviation(B()) ' mean ~ 0.5 std deviation ~0.28
DisplayMeanAndStdDeviation((0,0,14,14)) ' mean = 7 std deviation = 7
DisplayMeanAndStdDeviation((0,6,8,14)) ' mean = 7 std deviation = 5
DisplayMeanAndStdDeviation((6,6,8,8)) ' mean = 7 std deviation = 1
Sub DisplayMeanAndStdDeviation(A)
\\ push to stack all items of an array (need an array pointer)
Push ! StdDev(A)
\\ read from strack two numbers
Print "Mean is "; Number
Print "Standard Deviation is "; Number
End Sub
}
Checkit
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Maple
|
Maple
|
with(Statistics):
Sample(Normal(1, 0.5), 1000);
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#Nanoquery
|
Nanoquery
|
import Nanoquery.IO
import dict
def get_config(fname)
f = new(File).open(fname)
lines = split(f.readAll(), "\n")
values = new(Dict)
for line in lines
line = trim(line)
if len(line) > 0
if not (line .startswith. "#") or (line .startswith. ";")
tokens = split(line, " ")
if len(tokens) = 1
values.add(upper(tokens[0]), true)
else
parameters = list()
parameter = ""
for i in range(1, len(tokens) - 1)
parameter += tokens[i] + " "
if parameter .endswith. ", "
parameter = parameter.substring(0, len(parameter) - 2)
parameters.append(trim(parameter))
parameter = ""
end
end
parameters.append(trim(parameter))
if len(parameters) > 1
values.add(upper(tokens[0]), parameters)
else
values.add(upper(tokens[0]), parameters[0])
end
end
end
end
end
return values
end
println get_config(args[2])
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Julia
|
Julia
|
slurp(s) = readcsv(IOBuffer(s))
conv(s)= colon(map(x->parse(Int,x),match(r"^(-?\d+)-(-?\d+)$", s).captures)...)
expand(s) = mapreduce(x -> isa(x,Number)? Int(x) : conv(x), vcat, slurp(s))
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Liberty_BASIC
|
Liberty BASIC
|
filedialog "Open","*.txt",file$
if file$="" then end
open file$ for input as #f
while not(eof(#f))
line input #f, t$
print t$
wend
close #f
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#PureBasic
|
PureBasic
|
Debug ReverseString("!dekrow tI")
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Common_Lisp
|
Common Lisp
|
(defstruct (queue (:constructor %make-queue))
(items '() :type list)
(tail '() :type list))
(defun make-queue ()
"Returns an empty queue."
(%make-queue))
(defun queue-empty-p (queue)
"Returns true if the queue is empty."
(endp (queue-items queue)))
(defun enqueue (item queue)
"Enqueue item in queue. Returns the queue."
(prog1 queue
(if (queue-empty-p queue)
(setf (queue-items queue) (list item)
(queue-tail queue) (queue-items queue))
(setf (cdr (queue-tail queue)) (list item)
(queue-tail queue) (cdr (queue-tail queue))))))
(defun dequeue (queue)
"Dequeues an item from queue. Signals an error if queue is empty."
(if (queue-empty-p queue)
(error "Cannot dequeue from empty queue.")
(pop (queue-items queue))))
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#Elena
|
Elena
|
import system'math;
import extensions;
import extensions'text;
struct Quaternion
{
rprop real A;
rprop real B;
rprop real C;
rprop real D;
constructor new(a, b, c, d)
<= new(cast real(a), cast real(b), cast real(c), cast real(d));
constructor new(real a, real b, real c, real d)
{
A := a;
B := b;
C := c;
D := d
}
constructor(real r)
{
A := r;
B := 0.0r;
C := 0.0r;
D := 0.0r
}
real Norm = (A*A + B*B + C*C + D*D).sqrt();
Quaternion Negative = Quaternion.new(A.Negative,B.Negative,C.Negative,D.Negative);
Quaternion Conjugate = Quaternion.new(A,B.Negative,C.Negative,D.Negative);
Quaternion add(Quaternion q)
= Quaternion.new(A + q.A, B + q.B, C + q.C, D + q.D);
Quaternion multiply(Quaternion q)
= Quaternion.new(
A * q.A - B * q.B - C * q.C - D * q.D,
A * q.B + B * q.A + C * q.D - D * q.C,
A * q.C - B * q.D + C * q.A + D * q.B,
A * q.D + B * q.C - C * q.B + D * q.A);
Quaternion add(real r)
<= add(Quaternion.new(r,0,0,0));
Quaternion multiply(real r)
<= multiply(Quaternion.new(r,0,0,0));
bool equal(Quaternion q)
= (A == q.A) && (B == q.B) && (C == q.C) && (D == q.D);
string toPrintable()
= new StringWriter().printFormatted("Q({0}, {1}, {2}, {3})",A,B,C,D);
}
public program()
{
auto q := Quaternion.new(1,2,3,4);
auto q1 := Quaternion.new(2,3,4,5);
auto q2 := Quaternion.new(3,4,5,6);
real r := 7;
console.printLine("q = ", q);
console.printLine("q1 = ", q1);
console.printLine("q2 = ", q2);
console.printLine("r = ", r);
console.printLine("q.Norm() = ", q.Norm);
console.printLine("q1.Norm() = ", q1.Norm);
console.printLine("q2.Norm() = ", q2.Norm);
console.printLine("-q = ", q.Negative);
console.printLine("q.Conjugate() = ", q.Conjugate);
console.printLine("q + r = ", q + r);
console.printLine("q1 + q2 = ", q1 + q2);
console.printLine("q2 + q1 = ", q2 + q1);
console.printLine("q * r = ", q * r);
console.printLine("q1 * q2 = ", q1 * q2);
console.printLine("q2 * q1 = ", q2 * q1);
console.printLineFormatted("q1*q2 {0} q2*q1", ((q1 * q2) == (q2 * q1)).iif("==","!="))
}
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#Bracmat
|
Bracmat
|
quine$
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Lua
|
Lua
|
q = Queue.new()
Queue.push( q, 5 )
Queue.push( q, "abc" )
while not Queue.empty( q ) do
print( Queue.pop( q ) )
end
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#M2000_Interpreter
|
M2000 Interpreter
|
Module CheckStackAsQueue {
a=stack
Stack a {
Push 1, 2, 3
Print number=3
Print number=2
Print number=1
Print Empty=True
Push "A", "B", "C"
Print letter$="C"
Print letter$="B"
Print letter$="A"
Print Empty=True
Push 1,"OK"
}
Print Len(a)=2, StackItem(a, 2)=1, StackItem$(a, 1)="OK"
Print StackType$(a, 1)="String", StackType$(a,2)="Number"
}
CheckStackAsQueue
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#jq
|
jq
|
# Emit the k-th smallest item in the input array,
# or nothing if k is too small or too large.
# The smallest corresponds to k==1.
# The input array may hold arbitrary JSON entities, including null.
def quickselect(k):
def partition(pivot):
reduce .[] as $x
# state: [less, other]
( [ [], [] ]; # two empty arrays:
if $x < pivot
then .[0] += [$x] # add x to less
else .[1] += [$x] # add x to other
end
);
# recursive inner function has arity 0 for efficiency
def qs: # state: [kn, array] where kn counts from 0
.[0] as $kn
| .[1] as $a
| $a[0] as $pivot
| ($a[1:] | partition($pivot)) as $p
| $p[0] as $left
| ($left|length) as $ll
| if $kn == $ll then $pivot
elif $kn < $ll then [$kn, $left] | qs
else [$kn - $ll - 1, $p[1] ] | qs
end;
if length < k or k <= 0 then empty else [k-1, .] | qs end;
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Julia
|
Julia
|
v = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
@show v partialsort(v, 1:10)
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#Gambas
|
Gambas
|
siInput As New Short[]
siInput1 As Short[] = [0, 1, 2, 4, 6, 7, 8, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39]
siInput2 As Short[] = [-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20]
sOutput As New String[]
siCount As Short
siNum As Short
'__________________
Public Sub Main()
Dim siLoop As Short
For siLoop = 0 To 1
If siLoop = 0 Then siInput = siInput1.Copy() Else siInput = siInput2.Copy()
siCount = 0
siNum = 0
Repeat
If siInput[siCount + 1] = siInput[siCount] + 1 Then
Inc siCount
Else
GetOutput
Endif
Until siCount = siInput.Max
GetOutput
Print sOutput.join(", ")
sOutput.clear
Next
End
'__________________
Public Sub GetOutput()
If siNum = siCount Then
sOutput.add(siInput[siNum])
Inc siCount
siNum = siCount
End If
If siNum <> siCount Then
If siNum = siCount - 1 Then
sOutput.add(siInput[siNum])
sOutput.add(siInput[siNum + 1])
siCount += 2
siNum += 2
Return
End If
sOutput.Add(siInput[siNum] & "-" & siInput[siCount])
Inc siCount
siNum = siCount
End If
End
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Mathematica.2FWolfram_Language
|
Mathematica/Wolfram Language
|
RandomReal[NormalDistribution[1, 1/2], 1000]
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#MATLAB
|
MATLAB
|
mu = 1; sd = 0.5;
x = randn(1000,1) * sd + mu;
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#Nim
|
Nim
|
import re, strformat, strutils, tables
var configs: OrderedTable[string, seq[string]]
var parsed: seq[string]
for line in "demo.config".lines():
let line = line.strip()
if line != "" and not line.startswith(re"#|;"):
parsed = line.split(re"\s*=\s*|\s+", 1)
configs[parsed[0].toLower()] = if len(parsed) > 1: parsed[1].split(re"\s*,\s*") else: @[]
for key in ["fullname", "favouritefruit", "needspeeling", "seedsremoved", "otherfamily"]:
if not configs.hasKey(key):
echo(&"{key} = false")
else:
case len(configs[key])
of 0:
echo(&"{key} = true")
of 1:
echo(&"{key} = {configs[key][0]}")
else:
for i, v in configs[key].pairs():
echo(&"{key}({i+1}) = {v}")
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#K
|
K
|
grp : {1_'(&x=*x)_ x:",",x}
pos : {:[3=l:#p:&"-"=x;0,p@1;2=l;p;0=*p;,0;0,p]}
conv: 0${(x;1_ y)}/'{(pos x)_ x}'
expd: {,/@[x;&2=#:'x;{(*x)+!1+,/-':x}]}
rnge: {expd@conv grp x}
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Kotlin
|
Kotlin
|
// version 1.0.6
fun expandRange(s: String): MutableList<Int> {
val list = mutableListOf<Int>()
val items = s.split(',')
var first: Int
var last: Int
for (item in items) {
val count = item.count { it == '-' }
if (count == 0 || (count == 1 && item[0] == '-'))
list.add(item.toInt())
else {
val items2 = item.split('-')
if (count == 1) {
first = items2[0].toInt()
last = items2[1].toInt()
}
else if (count == 2) {
first = items2[1].toInt() * -1
last = items2[2].toInt()
}
else {
first = items2[1].toInt() * -1
last = items2[3].toInt() * -1
}
for (i in first..last) list.add(i)
}
}
return list
}
fun main(args: Array<String>) {
val s = "-6,-3--1,3-5,7-11,14,15,17-20"
println(expandRange(s))
}
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Lingo
|
Lingo
|
fp = xtra("fileIO").new()
fp.openFile(_movie.path & "input.txt", 1)
fileSize = fp.getLength()
repeat while TRUE
str = fp.readLine()
if str.char[1] = numtochar(10) then delete char 1 of str
if the last char of str = numtochar(13) then delete the last char of str
put str
if fp.getPosition()>=fileSize then exit repeat
end repeat
fp.closeFile()
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#LiveCode
|
LiveCode
|
command readFileLineByLine
local tFile, tLines, startRead
put "/usr/share/dict/words" into tFile
open file tFile for text read
put true into startRead
repeat until it is empty and startRead is false
put false into startRead
read from file tFile for 1 line
add 1 to tLines
end repeat
close file tFile
put tLines
end readFileLineByLine
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#Python
|
Python
|
input()[::-1]
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Component_Pascal
|
Component Pascal
|
MODULE Queue;
IMPORT
Boxes;
TYPE
Instance* = POINTER TO LIMITED RECORD
size: LONGINT;
first,last: LONGINT;
_queue: POINTER TO ARRAY OF Boxes.Box;
END;
PROCEDURE (self: Instance) Initialize(capacity: LONGINT),NEW;
BEGIN
self.size := 0;
self.first := 0;
self.last := 0;
NEW(self._queue,capacity)
END Initialize;
PROCEDURE New*(capacity: LONGINT): Instance;
VAR
aQueue: Instance;
BEGIN
NEW(aQueue);aQueue.Initialize(capacity);RETURN aQueue
END New;
PROCEDURE (self: Instance) IsEmpty*(): BOOLEAN, NEW;
BEGIN
RETURN self.size = 0;
END IsEmpty;
PROCEDURE (self: Instance) Capacity*(): LONGINT, NEW;
BEGIN
RETURN LEN(self._queue)
END Capacity;
PROCEDURE (self: Instance) Size*(): LONGINT, NEW;
BEGIN
RETURN self.size
END Size;
PROCEDURE (self: Instance) IsFull*(): BOOLEAN, NEW;
BEGIN
RETURN self.size = self.Capacity()
END IsFull;
PROCEDURE (self: Instance) Push*(b: Boxes.Box), NEW;
VAR
i, j, newCapacity, oldSize: LONGINT;
queue: POINTER TO ARRAY OF Boxes.Box;
BEGIN
INC(self.size);
self._queue[self.last] := b;
self.last := (self.last + 1) MOD self.Capacity();
IF self.IsFull() THEN
(* grow queue *)
newCapacity := self.Capacity() + (self.Capacity() DIV 2);
(* new queue *)
NEW(queue,newCapacity);
(* move data from old to new queue *)
i := self.first; j := 0; oldSize := self.Capacity() - self.first + self.last;
WHILE (j < oldSize) & (j < newCapacity - 1) DO
queue[j] := self._queue[i];
i := (i + 1) MOD newCapacity;INC(j)
END;
self._queue := queue;self.first := 0;self.last := j
END
END Push;
PROCEDURE (self: Instance) Pop*(): Boxes.Box, NEW;
VAR
b: Boxes.Box;
BEGIN
ASSERT(~self.IsEmpty());
DEC(self.size);
b := self._queue[self.first];
self._queue[self.first] := NIL;
self.first := (self.first + 1) MOD self.Capacity();
RETURN b
END Pop;
END Queue.
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#ERRE
|
ERRE
|
PROGRAM QUATERNION
!$DOUBLE
TYPE QUATERNION=(A,B,C,D)
DIM Q:QUATERNION,Q1:QUATERNION,Q2:QUATERNION
DIM R:QUATERNION,S:QUATERNION,T:QUATERNION
PROCEDURE NORM(T.->NORM)
NORM=SQR(T.A*T.A+T.B*T.B+T.C*T.C+T.D*T.D)
END PROCEDURE
PROCEDURE NEGATIVE(T.->T.)
T.A=-T.A
T.B=-T.B
T.C=-T.C
T.D=-T.D
END PROCEDURE
PROCEDURE CONJUGATE(T.->T.)
T.A=T.A
T.B=-T.B
T.C=-T.C
T.D=-T.D
END PROCEDURE
PROCEDURE ADD_REAL(T.,REAL->T.)
T.A=T.A+REAL
T.B=T.B
T.C=T.C
T.D=T.D
END PROCEDURE
PROCEDURE ADD(T.,S.->T.)
T.A=T.A+S.A
T.B=T.B+S.B
T.C=T.C+S.C
T.D=T.D+S.D
END PROCEDURE
PROCEDURE MULT_REAL(T.,REAL->T.)
T.A=T.A*REAL
T.B=T.B*REAL
T.C=T.C*REAL
T.D=T.D*REAL
END PROCEDURE
PROCEDURE MULT(T.,S.->R.)
R.A=T.A*S.A-T.B*S.B-T.C*S.C-T.D*S.D
R.B=T.A*S.B+T.B*S.A+T.C*S.D-T.D*S.C
R.C=T.A*S.C-T.B*S.D+T.C*S.A+T.D*S.B
R.D=T.A*S.D+T.B*S.C-T.C*S.B+T.D*S.A
END PROCEDURE
PROCEDURE PRINTQ(T.)
PRINT("(";T.A;",";T.B;",";T.C;",";T.D;")")
END PROCEDURE
BEGIN
Q.A=1 Q.B=2 Q.C=3 Q.D=4
Q1.A=2 Q1.B=3 Q1.C=4 Q1.D=5
Q2.A=3 Q2.B=4 Q2.C=5 Q2.D=6
REAL=7
NORM(Q.->NORM)
PRINT("Norm(q)=";NORM)
NEGATIVE(Q.->T.)
PRINT("Negative(q) =";)
PRINTQ(T.)
CONJUGATE(Q.->T.)
PRINT("Conjugate(q) =";)
PRINTQ(T.)
ADD_REAL(Q.,REAL->T.)
PRINT("q + real =";)
PRINTQ(T.)
! addition is commutative
ADD(Q1.,Q2.->T.)
PRINT("q1 + q2 =";)
PRINTQ(T.)
ADD(Q2.,Q1.->T.)
PRINT("q2 + q1 = ";)
PRINTQ(T.)
MULT_REAL(Q.,REAL->T.)
PRINT("q * real =";)
PRINTQ(T.)
! multiplication is not commutative
MULT(Q1.,Q2.->R.)
PRINT("q1 * q2=";)
PRINTQ(R.)
MULT(Q2.,Q1.->R.)
PRINT("q2 * q1=";)
PRINTQ(R.)
END PROGRAM
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#Brainf.2A.2A.2A
|
Brainf***
|
->+>+++>>+>++>+>+++>>+>++>>>+>+>+>++>+>>>>+++>+>>++>+>+++>>++>++>>+>>+>++>++>+>>>>+++>+>>>>++>++>>>>+>>++>+>+++>>>++>>++++++>>+>>++>
+>>>>+++>>+++++>>+>+++>>>++>>++>>+>>++>+>+++>>>++>>+++++++++++++>>+>>++>+>+++>+>+++>>>++>>++++>>+>>++>+>>>>+++>>+++++>>>>++>>>>+>+>+
+>>+++>+>>>>+++>+>>>>+++>+>>>>+++>>++>++>+>+++>+>++>++>>>>>>++>+>+++>>>>>+++>>>++>+>+++>+>+>++>>>>>>++>>>+>>>++>+>>>>+++>+>>>+>>++>+
>++++++++++++++++++>>>>+>+>>>+>>++>+>+++>>>++>>++++++++>>+>>++>+>>>>+++>>++++++>>>+>++>>+++>+>+>++>+>+++>>>>>+++>>>+>+>>++>+>+++>>>+
+>>++++++++>>+>>++>+>>>>+++>>++++>>+>+++>>>>>>++>+>+++>>+>++>>>>+>+>++>+>>>>+++>>+++>>>+[[->>+<<]<+]+++++[->+++++++++<]>.[+]>>
[<<+++++++[->+++++++++<]>-.------------------->-[-<.<+>>]<[+]<+>>>]<<<[-[-[-[>>+<++++++[->+++++<]]>++++++++++++++<]>+++<]++++++
[->+++++++<]>+<<<-[->>>++<<<]>[->>.<<]<<]
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Maple
|
Maple
|
q := queue[new]();
queue[enqueue](q,1);
queue[enqueue](q,2);
queue[enqueue](q,3);
queue[empty](q);
>>>false
queue[dequeue](q);
>>>1
queue[dequeue](q);
>>>2
queue[dequeue](q);
>>>3
queue[empty](q);
>>>true
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Mathematica.2FWolfram_Language
|
Mathematica/Wolfram Language
|
Empty[a_] := If[Length[a] == 0, True, False]
SetAttributes[Push, HoldAll]; Push[a_, elem_] := AppendTo[a, elem]
SetAttributes[Pop, HoldAllComplete]; Pop[a_] := If[EmptyQ[a], False, b = First[a]; Set[a, Most[a]]; b]
Queue = {}
-> {}
Empty[Queue]
-> True
Push[Queue, "1"]
-> {"1"}
EmptyQ[Queue]
->False
Pop[Queue]
->1
Pop[Queue]
->False
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Kotlin
|
Kotlin
|
// version 1.1.2
const val MAX = Int.MAX_VALUE
val rand = java.util.Random()
fun partition(list:IntArray, left: Int, right:Int, pivotIndex: Int): Int {
val pivotValue = list[pivotIndex]
list[pivotIndex] = list[right]
list[right] = pivotValue
var storeIndex = left
for (i in left until right) {
if (list[i] < pivotValue) {
val tmp = list[storeIndex]
list[storeIndex] = list[i]
list[i] = tmp
storeIndex++
}
}
val temp = list[right]
list[right] = list[storeIndex]
list[storeIndex] = temp
return storeIndex
}
tailrec fun quickSelect(list: IntArray, left: Int, right: Int, k: Int): Int {
if (left == right) return list[left]
var pivotIndex = left + Math.floor((rand.nextInt(MAX) % (right - left + 1)).toDouble()).toInt()
pivotIndex = partition(list, left, right, pivotIndex)
if (k == pivotIndex)
return list[k]
else if (k < pivotIndex)
return quickSelect(list, left, pivotIndex - 1, k)
else
return quickSelect(list, pivotIndex + 1, right, k)
}
fun main(args: Array<String>) {
val list = intArrayOf(9, 8, 7, 6, 5, 0, 1, 2, 3, 4)
val right = list.size - 1
for (k in 0..9) {
print(quickSelect(list, 0, right, k))
if (k < 9) print(", ")
}
println()
}
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#Go
|
Go
|
package main
import (
"errors"
"fmt"
"strconv"
"strings"
)
func main() {
rf, err := rangeFormat([]int{
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39,
})
if err != nil {
fmt.Println(err)
return
}
fmt.Println("range format:", rf)
}
func rangeFormat(a []int) (string, error) {
if len(a) == 0 {
return "", nil
}
var parts []string
for n1 := 0; ; {
n2 := n1 + 1
for n2 < len(a) && a[n2] == a[n2-1]+1 {
n2++
}
s := strconv.Itoa(a[n1])
if n2 == n1+2 {
s += "," + strconv.Itoa(a[n2-1])
} else if n2 > n1+2 {
s += "-" + strconv.Itoa(a[n2-1])
}
parts = append(parts, s)
if n2 == len(a) {
break
}
if a[n2] == a[n2-1] {
return "", errors.New(fmt.Sprintf(
"sequence repeats value %d", a[n2]))
}
if a[n2] < a[n2-1] {
return "", errors.New(fmt.Sprintf(
"sequence not ordered: %d < %d", a[n2], a[n2-1]))
}
n1 = n2
}
return strings.Join(parts, ","), nil
}
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Maxima
|
Maxima
|
load(distrib)$
random_normal(1.0, 0.5, 1000);
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#MAXScript
|
MAXScript
|
arr = #()
for i in 1 to 1000 do
(
a = random 0.0 1.0
b = random 0.0 1.0
c = 1.0 + 0.5 * sqrt (-2*log a) * cos (360*b) -- Maxscript cos takes degrees
append arr c
)
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#OCaml
|
OCaml
|
#use "topfind"
#require "inifiles"
open Inifiles
let print_field ini (label, field) =
try
let v = ini#getval "params" field in
Printf.printf "%s: %s\n" label v
with Invalid_element _ ->
Printf.printf "%s: not defined\n" label
let () =
let ini = new inifile "./conf.ini" in
let lst = [
"Full name", "FULLNAME";
"likes", "FAVOURITEFRUIT";
"needs peeling", "NEEDSPEELING";
"seeds removed", "SEEDSREMOVED";
] in
List.iter (print_field ini) lst;
let v = ini#getaval "params" "OTHERFAMILY" in
print_endline "other family:";
List.iter (Printf.printf "- %s\n") v;
;;
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Lasso
|
Lasso
|
define range_expand(expression::string) => {
local(parts) = regexp(`^(-?\d+)-(-?\d+)$`)
return (
with elm in #expression->split(`,`)
let isRange = #parts->setInput(#elm)&matches
select #isRange
? (integer(#parts->matchString(1)) to integer(#parts->matchString(2)))->asString
| integer(#elm)->asString
)->join(', ')
}
range_expand(`-6,-3--1,3-5,7-11,14,15,17-20`)
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Liberty_BASIC
|
Liberty BASIC
|
print ExpandRange$( "-6,-3--1,3-5,7-11,14,15,17-20")
end
function ExpandRange$( compressed$)
for i = 1 to ItemCount( compressed$, ",")
item$ = word$( compressed$, i, ",")
dash = instr( item$, "-", 2) 'dash that is not the first character, is a separator
if dash then
for k = val( left$( item$, dash - 1)) to val( mid$( item$, dash + 1))
ExpandRange$ = ExpandRange$ + str$( k) + ","
next k
else
ExpandRange$ = ExpandRange$ + item$ + ","
end if
next i
ExpandRange$ = left$( ExpandRange$, len( ExpandRange$) - 1)
end function
function ItemCount( list$, separator$)
while word$(list$, ItemCount + 1, separator$) <> ""
ItemCount = ItemCount + 1
wend
end function
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Logo
|
Logo
|
while [not eof?] [print readline]
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Lua
|
Lua
|
filename = "input.txt"
fp = io.open( filename, "r" )
for line in fp:lines() do
print( line )
end
fp:close()
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#Quackery
|
Quackery
|
[ dup nest? if
[ [] swap witheach
[ nested
swap join ] ] ] is reverse ( x --> x )
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Cowgol
|
Cowgol
|
include "strings.coh";
include "malloc.coh";
# Define types. The calling code is expected to provide a QueueData type.
record QueueItem is
data: QueueData;
next: [QueueItem];
end record;
record QueueMeta is
head: [QueueItem];
tail: [QueueItem];
end record;
typedef Queue is [QueueMeta];
const Q_NONE := 0 as [QueueItem];
# Allocate and free the queue datastructure.
sub MakeQueue(): (q: Queue) is
q := Alloc(@bytesof QueueMeta) as Queue;
q.head := Q_NONE;
q.tail := Q_NONE;
end sub;
sub FreeQueue(q: Queue) is
var cur := q.head;
while cur != Q_NONE loop
var next := cur.next;
Free(cur as [uint8]);
cur := next;
end loop;
Free(q as [uint8]);
end sub;
# Check if queue is empty.
sub QueueEmpty(q: Queue): (r: uint8) is
r := 0;
if q.head == Q_NONE then
r := 1;
end if;
end sub;
# Enqueue and dequeue data. Cowgol has no exceptions, so the calling code
# should check QueueEmpty first.
sub Enqueue(q: Queue, d: QueueData) is
var item := Alloc(@bytesof QueueItem) as [QueueItem];
item.data := d;
item.next := Q_NONE;
if q.head == Q_NONE then
q.head := item;
else
q.tail.next := item;
end if;
q.tail := item;
end sub;
sub Dequeue(q: Queue): (d: QueueData) is
d := q.head.data;
var cur := q.head;
q.head := q.head.next;
Free(cur as [uint8]);
if q.head == Q_NONE then
q.tail := Q_NONE;
end if;
end sub;
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#Euphoria
|
Euphoria
|
function norm(sequence q)
return sqrt(power(q[1],2)+power(q[2],2)+power(q[3],2)+power(q[4],2))
end function
function conj(sequence q)
q[2..4] = -q[2..4]
return q
end function
function add(object q1, object q2)
if atom(q1) != atom(q2) then
if atom(q1) then
q1 = {q1,0,0,0}
else
q2 = {q2,0,0,0}
end if
end if
return q1+q2
end function
function mul(object q1, object q2)
if sequence(q1) and sequence(q2) then
return { q1[1]*q2[1] - q1[2]*q2[2] - q1[3]*q2[3] - q1[4]*q2[4],
q1[1]*q2[2] + q1[2]*q2[1] + q1[3]*q2[4] - q1[4]*q2[3],
q1[1]*q2[3] - q1[2]*q2[4] + q1[3]*q2[1] + q1[4]*q2[2],
q1[1]*q2[4] + q1[2]*q2[3] - q1[3]*q2[2] + q1[4]*q2[1] }
else
return q1*q2
end if
end function
function quats(sequence q)
return sprintf("%g + %gi + %gj + %gk",q)
end function
constant
q = {1, 2, 3, 4},
q1 = {2, 3, 4, 5},
q2 = {5, 6, 7, 8},
r = 7
printf(1, "norm(q) = %g\n", norm(q))
printf(1, "-q = %s\n", {quats(-q)})
printf(1, "conj(q) = %s\n", {quats(conj(q))})
printf(1, "q + r = %s\n", {quats(add(q,r))})
printf(1, "q1 + q2 = %s\n", {quats(add(q1,q2))})
printf(1, "q1 * q2 = %s\n", {quats(mul(q1,q2))})
printf(1, "q2 * q1 = %s\n", {quats(mul(q2,q1))})
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#Burlesque
|
Burlesque
|
blsq ) "I'm a quine."
"I'm a quine."
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Nemerle
|
Nemerle
|
mutable q = Queue(); // or use immutable version as per Haskell example
def empty = q.IsEmpty(); // true at this point
q.Push(empty); // or Enqueue(), or Add()
def a = q.Pop(); // or Dequeue() or Take()
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#NetRexx
|
NetRexx
|
/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
-- Queue Usage Demonstration Program -------------------------------------------
method main(args = String[]) public constant
kew = RCQueueImpl()
do
say kew.pop()
catch ex = IndexOutOfBoundsException
say ex.getMessage
say
end
melancholyDane = ''
melancholyDane[0] = 4
melancholyDane[1] = 'To be'
melancholyDane[2] = 'or'
melancholyDane[3] = 'not to be?'
melancholyDane[4] = 'That is the question.'
loop p_ = melancholyDane[0] to 1 by -1
kew.push(melancholyDane[p_])
end p_
loop while \kew.empty
popped = kew.pop
say popped '\-'
end
say; say
-- demonstrate stowing something other than a text string in the queue
kew.push(melancholyDane)
md = kew.pop
loop l_ = 1 to md[0]
say md[l_] '\-'
end l_
say
return
-- Queue implementation --------------------------------------------------------
class RCQueueImpl
properties private
qqq = Deque
method RCQueueImpl() public
qqq = ArrayDeque()
return
method push(stuff) public
qqq.push(stuff)
return
method pop() public returns Rexx signals IndexOutOfBoundsException
if qqq.isEmpty then signal IndexOutOfBoundsException('The queue is empty')
return Rexx qqq.pop()
method empty() public binary returns boolean
return qqq.isEmpty
method isTrue public constant binary returns boolean
return 1 == 1
method isFalse public constant binary returns boolean
return \isTrue
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Lua
|
Lua
|
function partition (list, left, right, pivotIndex)
local pivotValue = list[pivotIndex]
list[pivotIndex], list[right] = list[right], list[pivotIndex]
local storeIndex = left
for i = left, right do
if list[i] < pivotValue then
list[storeIndex], list[i] = list[i], list[storeIndex]
storeIndex = storeIndex + 1
end
end
list[right], list[storeIndex] = list[storeIndex], list[right]
return storeIndex
end
function quickSelect (list, left, right, n)
local pivotIndex
while 1 do
if left == right then return list[left] end
pivotIndex = math.random(left, right)
pivotIndex = partition(list, left, right, pivotIndex)
if n == pivotIndex then
return list[n]
elseif n < pivotIndex then
right = pivotIndex - 1
else
left = pivotIndex + 1
end
end
end
math.randomseed(os.time())
local vec = {9, 8, 7, 6, 5, 0, 1, 2, 3, 4}
for i = 1, 10 do print(i, quickSelect(vec, 1, #vec, i) .. " ") end
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#Groovy
|
Groovy
|
def range = { s, e -> s == e ? "${s}," : s == e - 1 ? "${s},${e}," : "${s}-${e}," }
def compressList = { list ->
def sb, start, end
(sb, start, end) = [''<<'', list[0], list[0]]
for (i in list[1..-1]) {
(sb, start, end) = i == end + 1 ? [sb, start, i] : [sb << range(start, end), i, i]
}
(sb << range(start, end))[0..-2].toString()
}
def compressRanges = { expanded -> compressList(Eval.me('[' + expanded + ']')) }
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Metafont
|
Metafont
|
numeric col[];
m := 0; % m holds the mean, for testing purposes
for i = 1 upto 1000:
col[i] := 1 + .5normaldeviate;
m := m + col[i];
endfor
% testing
m := m / 1000; % finalize the computation of the mean
s := 0; % in s we compute the standard deviation
for i = 1 upto 1000:
s := s + (col[i] - m)**2;
endfor
s := sqrt(s / 1000);
show m, s; % and let's show that really they get what we wanted
end
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#MiniScript
|
MiniScript
|
randNormal = function(mean=0, stddev=1)
return mean + sqrt(-2 * log(rnd,2.7182818284)) * cos(2*pi*rnd) * stddev
end function
x = []
for i in range(1,1000)
x.push randNormal(1, 0.5)
end for
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#ooRexx
|
ooRexx
|
#!/usr/bin/rexx
/*.----------------------------------------------------------------------.*/
/*|readconfig: Read keyword value pairs from a configuration file into |*/
/*| Rexx variables. |*/
/*| |*/
/*|Usage: |*/
/*| .-~/rosetta.conf-. |*/
/*|>>-readconfig-+----------------+------------------------------------><|*/
/*| |-configfilename-| |*/
/*| |-- -? ----------| |*/
/*| |-- -h ----------| |*/
/*| '- --help -------' |*/
/*| |*/
/*|where |*/
/*| configfilename |*/
/*| is the name of the configuration file to be processed. if not|*/
/*| specified, ~/rosetta.conf is used. |*/
/*| |*/
/*|All values retrieved from the configuration file are stored in |*/
/*|compound variables with the stem config. Variables with multiple |*/
/*|values have a numeric index appended, and the highest index number |*/
/*|is stored in the variable with index 0; e.g. if CONFIG.OTHERFAMILY.1 |*/
/*|and CONFIG.OTHERFAMILY.2 have values assigned, CONFIG.OTHERFAMILY.0 = |*/
/*|2. |*/
/*|-?, -h or --help all cause this documentation to be displayed. |*/
/*| |*/
/*|This program was tested using Open Object Rexx 4.1.1. It should work |*/
/*|with most other dialects as well. |*/
/*'----------------------------------------------------------------------'*/
call usage arg(1)
trace normal
signal on any name error
/* Prepare for processing the configuration file. */
keywords = 'FULLNAME FAVOURITEFRUIT NEEDSPEELING SEEDSREMOVED OTHERFAMILY'
/* Set default values for configuration variables here */
config_single?. = 1
config. = ''
config.NEEDSPEELING = 0
config.SEEDSREMOVED = 1
/* Validate command line inputs. */
parse arg configfilename
if length(configfilename) = 0 then
configfilename = '~/rosetta.conf'
configfile = stream(configfilename,'COMMAND','QUERY EXISTS')
if length(configfile) = 0 then
do
say configfilename 'was not found.'
exit 28
end
signal on notready /* if an I/O error occurs. */
/* Open the configuration file. */
response = stream(configfile,'COMMAND','OPEN READ SHARED')
/* Parse the contents of the configuration file into variables. */
do while lines(configfile) > 0
statement = linein(configfile)
select
when left(statement,1) = '#',
| left(statement,1) = ';',
| length(strip(statement)) = 0,
then /* a comment or a blank line. */
nop /* skip it. */
otherwise
do
if pos('=',word(statement,1)) > 0,
| left(word(statement,2),1) = '=',
then /* a keyword/value pair with = between. */
parse var statement keyword '=' value
else /* a keyword/value pair with no =. */
parse var statement keyword value
keyword = translate(strip(keyword)) /* make it uppercase. */
single? = pos(',',value) = 0 /* a single value, or multiple values? */
call value 'CONFIG_single?.'keyword,single? /* remember. */
if single? then
do
if length(value) > 0 then
call value 'CONFIG.'keyword,strip(value)
end /* strip keeps internal whitespace only. */
else /* store each value with its index. */
do v = 1 by 1 while length(value) > 0
parse var value value1 ',' value
if length(value1) > 0 then
do
call value 'CONFIG.'keyword'.'v,strip(value1)
call value 'CONFIG.'keyword'.0',v /* remember this. */
end
end
end
end
end
/* Display the values of the configuration variables. */
say 'Values associated with configuration file' configfilename':'
say
do while words(keywords) > 0
parse var keywords keyword keywords
if value('CONFIG_single?.'keyword) then
say right(keyword,20) '= "'value('CONFIG.'keyword)'"'
else
do
lastv = value('CONFIG.'keyword'.0')
do v = 1 to lastv
say right(keyword,20-(length(v)+2))'['v'] = "'value('CONFIG.'keyword'.'v)'"'
end
end
end
say
notready: /* I/O errors come here. */
filestatus = stream(configfile,'STATE')
if filestatus \= 'READY' then
say 'An I/O error occurred; the file status is' filestatus'.'
response = stream(configfile,'COMMAND','CLOSE')
error:
/*? = sysdumpvariables() */ /* see everything Rexx used. */
exit
usage: procedure
trace normal
if arg(1) = '-h',
| arg(1) = '-?',
| arg(1) = '--help'
then
do
line = '/*|'
say
do l = 3 by 1 while line~left(3) = '/*|'
line = sourceline(l)
parse var line . '/*|' text '|*/' .
say text
end
say
exit 0
end
return
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Lingo
|
Lingo
|
-- Note: currently does not support extra white space in input string
on expandRange (str)
res = ""
_player.itemDelimiter = ","
cnt = str.item.count
repeat with i = 1 to cnt
part = str.item[i]
pos = offset("-", part.char[2..part.length])
if pos>0 then
a = integer(part.char[1..pos])
b = integer(part.char[pos+2..part.length])
repeat with j = a to b
put j&"," after res
end repeat
else
put part&"," after res
end if
end repeat
delete the last char of res
return res
end
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#LiveCode
|
LiveCode
|
function range beginning ending stepping
local tRange, tBegin, tEnd, tstep
if stepping is empty or stepping is 0 then
put 1 into tstep
else
put abs(stepping) into tstep
end if
if ending is empty or isNumber(ending) is not true then
put 0 into tEnd
else
put ending into tEnd
end if
if beginning is empty or isNumber(beginning) is not true then
put 0 into tBegin
else
put beginning into tBegin
end if
repeat with r = tBegin to tEnd step tstep
put space & r after tRange
end repeat
return word 1 to -1 of tRange
end range
function expandRange rangeExpr
put rangeExpr into tRange
split tRange by comma
repeat with n = 1 to the number of elements of tRange
if matchText(tRange[n],"^(\-*\d+)\-(\-*\d+)",beginning, ending) then
put range(beginning, ending, 1) & space after z
else
put tRange[n] & space after z
end if
end repeat
return z
end expandRange
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#M2000_Interpreter
|
M2000 Interpreter
|
Module checkit {
\\ prepare a file
document a$
a$={First Line
Second line
Third Line
}
Save.Doc a$, "checkthis.txt", 0 ' 0 for UTF-16LE
Flush
Open "checkthis.txt" For Wide Input as #F
While not Eof(#f) {
Data Seek(#f)
Line Input #F, b$
Print b$
}
Close #f
Dim Index()
\\ copy stack to index(), flush stack
Index()=Array([])
\\ change base to base 1
Dim Base 1, Index(len(index()))
Open "checkthis.txt" For Wide Input as #F
Seek#F, Index(2)
Line Input #F, b$
Print b$ ' print second line
Close #f
\\ prepare Ansi file
Print "Ansi File"
Save.Doc a$, "checkthis.txt", 1033 ' we use specific locale
Flush \\ flush the stack to get indexes
oldlocale=locale
locale 1033
\\ no Wide clause
Open "checkthis.txt" For Input as #F
While not Eof(#f) {
Data Seek(#f)
Line Input #F, b$
Print b$
}
Close #f
Dim Index()
\\ copy stack to index(), flush stack
Index()=Array([])
\\ change base to base 1
Dim Base 1, Index(len(index()))
Open "checkthis.txt" For Input as #F
Seek#F, Index(2)
Line Input #F, b$
Print b$ ' print second line
Close #f
locale oldlocale
}
checkit
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Maple
|
Maple
|
path := "file.txt":
while (true) do
input := readline(path):
if input = 0 then break; end if:
#The line is stored in input
end do:
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#Qi
|
Qi
|
(REVERSE "ABCD")
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#D
|
D
|
queue:
{ :start 0 :end 0 }
enqueue q item:
set-to q q!end item
set-to q :end ++ q!end
dequeue q:
if empty q:
Raise :value-error "popping from empty queue"
q! q!start
delete-from q q!start
set-to q :start ++ q!start
empty q:
= q!start q!end
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#F.23
|
F#
|
open System
[<Struct; StructuralEquality; NoComparison>]
type Quaternion(r : float, i : float, j : float, k : float) =
member this.A = r
member this.B = i
member this.C = j
member this.D = k
new (f : float) = Quaternion(f, 0., 0., 0.)
static member (~-) (q : Quaternion) = Quaternion(-q.A, -q.B, -q.C, -q.D)
static member (+) (q1 : Quaternion, q2 : Quaternion) =
Quaternion(q1.A + q2.A, q1.B + q2.B, q1.C + q2.C, q1.D + q2.D)
static member (+) (q : Quaternion, r : float) = q + Quaternion(r)
static member (+) (r : float, q: Quaternion) = Quaternion(r) + q
static member (*) (q1 : Quaternion, q2 : Quaternion) =
Quaternion(
q1.A * q2.A - q1.B * q2.B - q1.C * q2.C - q1.D * q2.D,
q1.A * q2.B + q1.B * q2.A + q1.C * q2.D - q1.D * q2.C,
q1.A * q2.C - q1.B * q2.D + q1.C * q2.A + q1.D * q2.B,
q1.A * q2.D + q1.B * q2.C - q1.C * q2.B + q1.D * q2.A)
static member (*) (q : Quaternion, r : float) = q * Quaternion(r)
static member (*) (r : float, q: Quaternion) = Quaternion(r) * q
member this.Norm = Math.Sqrt(r * r + i * i + j * j + k * k)
member this.Conjugate = Quaternion(r, -i, -j, -k)
override this.ToString() = sprintf "Q(%f, %f, %f, %f)" r i j k
[<EntryPoint>]
let main argv =
let q = Quaternion(1., 2., 3., 4.)
let q1 = Quaternion(2., 3., 4., 5.)
let q2 = Quaternion(3., 4., 5., 6.)
let r = 7.
printfn "q = %A" q
printfn "q1 = %A" q1
printfn "q2 = %A" q2
printfn "r = %A" r
printfn "q.Norm = %A" q.Norm
printfn "q1.Norm = %A" q1.Norm
printfn "q2.Norm = %A" q2.Norm
printfn "-q = %A" -q
printfn "q.Conjugate = %A" q.Conjugate
printfn "q + r = %A" (q + (Quaternion r))
printfn "q1 + q2 = %A" (q1 + q2)
printfn "q2 + q1 = %A" (q2 + q1)
printfn "q * r = %A" (q * r)
printfn "q1 * q2 = %A" (q1 * q2)
printfn "q2 * q1 = %A" (q2 * q1)
printfn "q1*q2 %s q2*q1" (if (q1 * q2) = (q2 * q1) then "=" else "<>")
printfn "q %s Q(1.,2.,3.,4.)" (if q = Quaternion(1., 2., 3., 4.) then "=" else "<>")
0
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#C
|
C
|
#include <stdio.h>
static char sym[] = "\n\t\\\"";
int main(void) {
const char *code = "#include <stdio.h>%c%cstatic char sym[] = %c%cn%ct%c%c%c%c%c;%c%cint main(void) {%c%cconst char *code = %c%s%c;%c%cprintf(code, sym[0], sym[0], sym[3], sym[2], sym[2], sym[2], sym[2], sym[2], sym[3], sym[3], sym[0], sym[0], sym[0], sym[1], sym[3], code, sym[3], sym[0], sym[1], sym[0], sym[0], sym[1], sym[0], sym[0]);%c%c%creturn 0;%c}%c";
printf(code, sym[0], sym[0], sym[3], sym[2], sym[2], sym[2], sym[2], sym[2], sym[3], sym[3], sym[0], sym[0], sym[0], sym[1], sym[3], code, sym[3], sym[0], sym[1], sym[0], sym[0], sym[1], sym[0], sym[0]);
return 0;
}
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Nim
|
Nim
|
import deques
var queue = initDeque[int]()
queue.addLast(26)
queue.addLast(99)
queue.addLast(2)
echo "Queue size: ", queue.len()
echo "Popping: ", queue.popFirst()
echo "Popping: ", queue.popFirst()
echo "Popping: ", queue.popFirst()
echo "Popping: ", queue.popFirst()
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Objeck
|
Objeck
|
class Test {
function : Main(args : String[]) ~ Nil {
q := Struct.IntQueue->New();
q->Add(1);
q->Add(2);
q->Add(3);
q->Remove()->PrintLine();
q->Remove()->PrintLine();
q->Remove()->PrintLine();
q->IsEmpty()->PrintLine();
}
}
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Maple
|
Maple
|
part := proc(arr, left, right, pivot)
local val,safe,i:
val := arr[pivot]:
arr[pivot], arr[right] := arr[right], arr[pivot]:
safe := left:
for i from left to right do
if arr[i] < val then
arr[safe], arr[i] := arr[i], arr[safe]:
safe := safe + 1:
end if:
end do:
arr[right], arr[safe] := arr[safe], arr[right]:
return safe:
end proc:
quickselect := proc(arr,k)
local pivot,left,right:
left,right := 1,numelems(arr):
while(true)do
if left = right then return arr[left]: end if:
pivot := trunc((left+right)/2);
pivot := part(arr, left, right, pivot):
if k = pivot then
return arr[k]:
elif k < pivot then
right := pivot-1:
else
left := pivot+1:
end if:
end do:
end proc:
roll := rand(1..20):
demo := Array([seq(roll(), i=1..20)]);
map(x->printf("%d ", x), demo):
print(quickselect(demo,7)):
print(quickselect(demo,14)):
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Mathematica_.2F_Wolfram_Language
|
Mathematica / Wolfram Language
|
Quickselect[ds : DataStructure["DynamicArray", _], k_] := QuickselectWorker[ds, 1, ds["Length"], k];
QuickselectWorker[ds_, low0_, high0_, k_] := Module[{pivotIdx, low = low0, high = high0},
While[True,
If[low === high,
Return[ds["Part", low]]
];
pivotIdx = SelectPartition[ds, low, high];
Which[k === pivotIdx,
Return[ds["Part", k]],
k < pivotIdx,
high = pivotIdx - 1,
True,
low = pivotIdx + 1
]
]
];
SelectPartition[ds_, low_, high_] := Module[{pivot = ds["Part", high], i = low, j},
Do[
If[ds["Part", j] <= pivot,
ds["SwapPart", i, j];
i = i + 1
]
,
{j, low, high - 1}
];
ds["SwapPart", i, high];
i
];
ds = CreateDataStructure["DynamicArray", {9, 8, 7, 6, 5, 0, 1, 2, 3, 4}];
Quickselect[ds, #] & /@ Range[10]
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#Haskell
|
Haskell
|
import Data.List (intercalate)
extractRange :: [Int] -> String
extractRange = intercalate "," . f
where f :: [Int] -> [String]
f (x1 : x2 : x3 : xs) | x1 + 1 == x2 && x2 + 1 == x3
= (show x1 ++ '-' : show xn) : f xs'
where (xn, xs') = g (x3 + 1) xs
g a (n : ns) | a == n = g (a + 1) ns
| otherwise = (a - 1, n : ns)
g a [] = (a - 1, [])
f (x : xs) = show x : f xs
f [] = []
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Mirah
|
Mirah
|
import java.util.Random
list = double[999]
mean = 1.0
std = 0.5
rng = Random.new
0.upto(998) do | i |
list[i] = mean + std * rng.nextGaussian
end
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#.D0.9C.D0.9A-61.2F52
|
МК-61/52
|
П7 <-> П8 1/x П6 ИП6 П9 СЧ П6 1/x
ln ИП8 * 2 * КвКор ИП9 2 * пи
* sin * ИП7 + С/П БП 05
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#Pascal
|
Pascal
|
#!/usr/bin/instantfpc
{$if not defined(fpc) or (fpc_fullversion < 20600)}
{$error FPC 2.6.0 or greater required}
{$endif}
{$mode objfpc}{$H+}
uses
Classes,SysUtils,gvector,ghashmap;
type
TStrHashCaseInsensitive = class
class function hash(s: String; n: Integer): Integer;
end;
class function TStrHashCaseInsensitive.hash(s: String; n: Integer): Integer;
var
x: Integer;
c: Char;
begin
x := 0;
for c in UpCase(s) do Inc(x,Ord(c));
Result := x mod n;
end;
type
TConfigValues = specialize TVector<String>;
TConfigStorage = class(specialize THashMap<String,TConfigValues,TStrHashCaseInsensitive>)
destructor Destroy; override;
end;
destructor TConfigStorage.Destroy;
var
It: TIterator;
begin
if Size > 0 then begin
It := Iterator;
repeat
It.Value.Free;
until not It.Next;
It.Free;
end;
inherited Destroy;
end;
var
ConfigStrings,ConfigValues: TStrings;
ConfigStorage: TConfigStorage;
ConfigLine,ConfigName,ConfigValue: String;
SeparatorPos: Integer;
begin
ConfigStrings := TStringList.Create;
ConfigValues := TStringList.Create;
ConfigValues.Delimiter := ',';
ConfigValues.StrictDelimiter := true;
ConfigStorage := TConfigStorage.Create;
ConfigStrings.LoadFromFile('config.test');
for ConfigLine in ConfigStrings do begin
if Length(ConfigLine) > 0 then begin
case ConfigLine[1] of
'#',';': ; // ignore
else begin
// look for = first
SeparatorPos := Pos('=',ConfigLine);
// if not found, then look for space
if SeparatorPos = 0 then begin
SeparatorPos := Pos(' ',ConfigLine);
end;
// found space
if SeparatorPos <> 0 then begin
ConfigName := UpCase(Copy(ConfigLine,1,SeparatorPos - 1));
ConfigValues.DelimitedText := Copy(ConfigLine,SeparatorPos + 1,Length(ConfigLine) - SeparatorPos);
// no = or space found, take the whole line as a key name
end else begin
ConfigName := UpCase(Trim(ConfigLine));
end;
if not ConfigStorage.Contains(ConfigName) then begin
ConfigStorage[ConfigName] := TConfigValues.Create;
end;
for ConfigValue in ConfigValues do begin
ConfigStorage[ConfigName].PushBack(Trim(ConfigValue));
end;
end;
end;
end;
end;
WriteLn('FULLNAME = ' + ConfigStorage['FULLNAME'][0]);
WriteLn('FAVOURITEFRUIT = ' + ConfigStorage['FAVOURITEFRUIT'][0]);
WriteLn('NEEDSPEELING = ' + BoolToStr(ConfigStorage.Contains('NEEDSPEELING'),true));
WriteLn('SEEDSREMOVED = ' + BoolToStr(ConfigStorage.Contains('SEEDSREMOVED'),true));
WriteLn('OTHERFAMILY(1) = ' + ConfigStorage['OTHERFAMILY'][0]);
WriteLn('OTHERFAMILY(2) = ' + ConfigStorage['OTHERFAMILY'][1]);
ConfigStorage.Free;
ConfigValues.Free;
ConfigStrings.Free;
end.
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Lua
|
Lua
|
function range(i, j)
local t = {}
for n = i, j, i<j and 1 or -1 do
t[#t+1] = n
end
return t
end
function expand_ranges(rspec)
local ptn = "([-+]?%d+)%s?-%s?([-+]?%d+)"
local t = {}
for v in string.gmatch(rspec, '[^,]+') do
local s, e = v:match(ptn)
if s == nil then
t[#t+1] = tonumber(v)
else
for i, n in ipairs(range(tonumber(s), tonumber(e))) do
t[#t+1] = n
end
end
end
return t
end
local ranges = "-6,-3--1,3-5,7-11,14,15,17-20"
print(table.concat(expand_ranges(ranges), ', '))
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Mathematica.2FWolfram_Language
|
Mathematica/Wolfram Language
|
strm=OpenRead["input.txt"];
If[strm=!=$Failed,
While[line=!=EndOfFile,
line=Read[strm];
(*Do something*)
]];
Close[strm];
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
fid = fopen('foobar.txt','r');
if (fid < 0)
printf('Error:could not open file\n')
else
while ~feof(fid),
line = fgetl(fid);
%% process line %%
end;
fclose(fid)
end;
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#R
|
R
|
revstring <- function(stringtorev) {
return(
paste(
strsplit(stringtorev,"")[[1]][nchar(stringtorev):1]
,collapse="")
)
}
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#D.C3.A9j.C3.A0_Vu
|
Déjà Vu
|
queue:
{ :start 0 :end 0 }
enqueue q item:
set-to q q!end item
set-to q :end ++ q!end
dequeue q:
if empty q:
Raise :value-error "popping from empty queue"
q! q!start
delete-from q q!start
set-to q :start ++ q!start
empty q:
= q!start q!end
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#Factor
|
Factor
|
USING: generalizations io kernel locals math.quaternions
math.vectors prettyprint sequences ;
IN: rosetta-code.quaternion-type
: show ( quot -- )
[ unparse 2 tail but-last "= " append write ] [ call . ] bi
; inline
: 2show ( quots -- )
[ 2curry show ] map-compose [ call ] each ; inline
: q+n ( q n -- q+n ) n>q q+ ;
[let
{ 1 2 3 4 } 7 { 2 3 4 5 } { 3 4 5 6 } :> ( q r q1 q2 )
q [ norm ]
q [ vneg ]
q [ qconjugate ]
[ curry show ] 2tri@
{
[ q r [ q+n ] ]
[ q r [ q*n ] ]
[ q1 q2 [ q+ ] ]
[ q1 q2 [ q* ] ]
[ q2 q1 [ q* ] ]
} 2show
]
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#C.23
|
C#
|
class Program { static void Main() { var s = "class Program {{ static void Main() {{ var s = {0}{1}{0}; System.Console.WriteLine(s, (char)34, s); }} }}"; System.Console.WriteLine(s, (char)34, s); } }
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#OCaml
|
OCaml
|
# let q = Queue.create ();;
val q : '_a Queue.t = <abstr>
# Queue.is_empty q;;
- : bool = true
# Queue.add 1 q;;
- : unit = ()
# Queue.is_empty q;;
- : bool = false
# Queue.add 2 q;;
- : unit = ()
# Queue.add 3 q;;
- : unit = ()
# Queue.peek q;;
- : int = 1
# Queue.length q;;
- : int = 3
# Queue.iter (Printf.printf "%d, ") q; print_newline ();;
1, 2, 3,
- : unit = ()
# Queue.take q;;
- : int = 1
# Queue.take q;;
- : int = 2
# Queue.peek q;;
- : int = 3
# Queue.length q;;
- : int = 1
# Queue.add 4 q;;
- : unit = ()
# Queue.take q;;
- : int = 3
# Queue.peek q;;
- : int = 4
# Queue.take q;;
- : int = 4
# Queue.is_empty q;;
- : bool = true
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Mercury
|
Mercury
|
%%%-------------------------------------------------------------------
:- module quickselect_task.
:- interface.
:- import_module io.
:- pred main(io, io).
:- mode main(di, uo) is det.
:- implementation.
:- import_module array.
:- import_module exception.
:- import_module int.
:- import_module list.
:- import_module random.
:- import_module random.sfc64.
:- import_module string.
%%%-------------------------------------------------------------------
%%%
%%% Partitioning a subarray into two halves: one with elements less
%%% than or equal to a pivot, the other with elements greater than or
%%% equal to a pivot.
%%%
%%% The implementation is tail-recursive.
%%%
:- pred partition(pred(T, T), T, int, int, array(T), array(T), int).
:- mode partition(pred(in, in) is semidet, in, in, in,
array_di, array_uo, out).
partition(Less_than, Pivot, I_first, I_last, Arr0, Arr, I_pivot) :-
I = I_first - 1,
J = I_last + 1,
partition_loop(Less_than, Pivot, I, J, Arr0, Arr, I_pivot).
:- pred partition_loop(pred(T, T), T, int, int,
array(T), array(T), int).
:- mode partition_loop(pred(in, in) is semidet, in, in, in,
array_di, array_uo, out).
partition_loop(Less_than, Pivot, I, J, Arr0, Arr, Pivot_index) :-
if (I = J) then (Arr = Arr0,
Pivot_index = I)
else (I1 = I + 1,
I2 = search_right(Less_than, Pivot, I1, J, Arr0),
(if (I2 = J) then (Arr = Arr0,
Pivot_index = J)
else (J1 = J - 1,
J2 = search_left(Less_than, Pivot, I2, J1, Arr0),
swap(I2, J2, Arr0, Arr1),
partition_loop(Less_than, Pivot, I2, J2, Arr1, Arr,
Pivot_index)))).
:- func search_right(pred(T, T), T, int, int, array(T)) = int.
:- mode search_right(pred(in, in) is semidet,
in, in, in, in) = out is det.
search_right(Less_than, Pivot, I, J, Arr0) = K :-
if (I = J) then (I = K)
else if Less_than(Pivot, Arr0^elem(I)) then (I = K)
else (search_right(Less_than, Pivot, I + 1, J, Arr0) = K).
:- func search_left(pred(T, T), T, int, int, array(T)) = int.
:- mode search_left(pred(in, in) is semidet,
in, in, in, in) = out is det.
search_left(Less_than, Pivot, I, J, Arr0) = K :-
if (I = J) then (J = K)
else if Less_than(Arr0^elem(J), Pivot) then (J = K)
else (search_left(Less_than, Pivot, I, J - 1, Arr0) = K).
%%%-------------------------------------------------------------------
%%%
%%% Quickselect with a random pivot.
%%%
%%% The implementation is tail-recursive. One has to pass the routine
%%% a random number generator of type M, attached to the IO state.
%%%
%%% I use a random pivot to get O(n) worst case *expected* running
%%% time. Code using a random pivot is easy to write and read, and for
%%% most purposes comes close enough to a criterion set by Scheme's
%%% SRFI-132: "Runs in O(n) time." (See
%%% https://srfi.schemers.org/srfi-132/srfi-132.html)
%%%
%%% Of course we are not bound here by SRFI-132, but still I respect
%%% it as a guide.
%%%
%%% A "median of medians" pivot gives O(n) running time, but is more
%%% complicated. (That is, of course, assuming you are not writing
%%% your own random number generator and making it a complicated one.)
%%%
%% quickselect/8 selects the (K+1)th largest element of Arr.
:- pred quickselect(pred(T, T)::pred(in, in) is semidet, int::in,
array(T)::array_di, array(T)::array_uo,
T::out, M::in, io::di, io::uo)
is det <= urandom(M, io).
quickselect(Less_than, K, Arr0, Arr, Elem, M, !IO) :-
bounds(Arr0, I_first, I_last),
quickselect(Less_than, I_first, I_last, K, Arr0, Arr, Elem, M, !IO).
%% quickselect/10 selects the (K+1)th largest element of
%% Arr[I_first..I_last].
:- pred quickselect(pred(T, T)::pred(in, in) is semidet,
int::in, int::in, int::in,
array(T)::array_di, array(T)::array_uo,
T::out, M::in, io::di, io::uo)
is det <= urandom(M, io).
quickselect(Less_than, I_first, I_last, K, Arr0, Arr, Elem, M, !IO) :-
if (0 =< K, K =< I_last - I_first)
then (K_adjusted_for_range = K + I_first,
quickselect_loop(Less_than, I_first, I_last,
K_adjusted_for_range,
Arr0, Arr, Elem, M, !IO))
else throw("out of range").
:- pred quickselect_loop(pred(T, T)::pred(in, in) is semidet,
int::in, int::in, int::in,
array(T)::array_di, array(T)::array_uo,
T::out, M::in, io::di, io::uo)
is det <= urandom(M, io).
quickselect_loop(Less_than, I_first, I_last, K,
Arr0, Arr, Elem, M, !IO) :-
if (I_first = I_last) then (Arr = Arr0,
Elem = Arr0^elem(I_first))
else (uniform_int_in_range(M, I_first, I_last - I_first + 1,
I_pivot, !IO),
Pivot = Arr0^elem(I_pivot),
%% Move the last element to where the pivot had been. Perhaps
%% the pivot was already the last element, of course. In any
%% case, we shall partition only from I_first to I_last - 1.
Elem_last = Arr0^elem(I_last),
Arr1 = (Arr0^elem(I_pivot) := Elem_last),
%% Partition the array in the range I_first..I_last - 1,
%% leaving out the last element (which now can be considered
%% garbage).
partition(Less_than, Pivot, I_first, I_last - 1, Arr1, Arr2,
I_final),
%% Now everything that is less than the pivot is to the left
%% of I_final.
%% Put the pivot at I_final, moving the element that had been
%% there to the end. If I_final = I_last, then this element is
%% actually garbage and will be overwritten with the pivot,
%% which turns out to be the greatest element. Otherwise, the
%% moved element is not less than the pivot and so the
%% partitioning is preserved.
Elem_to_move = Arr2^elem(I_final),
Arr3 = (Arr2^elem(I_last) := Elem_to_move),
Arr4 = (Arr3^elem(I_final) := Pivot),
%% Compare I_final and K, to see what to do next.
(if (I_final < K)
then quickselect_loop(Less_than, I_final + 1, I_last, K,
Arr4, Arr, Elem, M, !IO)
else if (K < I_final)
then quickselect_loop(Less_than, I_first, I_final - 1, K,
Arr4, Arr, Elem, M, !IO)
else (Arr = Arr4,
Elem = Arr4^elem(I_final)))).
%%%-------------------------------------------------------------------
:- func example_numbers = list(int).
example_numbers = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4].
main(!IO) :-
(sfc64.init(P, S)),
make_io_urandom(P, S, M, !IO),
Print_kth_greatest = (pred(K::in, di, uo) is det -->
print_kth_greatest(K, example_numbers, M)),
Print_kth_least = (pred(K::in, di, uo) is det -->
print_kth_least(K, example_numbers, M)),
print("With < as order predicate: ", !IO),
foldl(Print_kth_least, 1 `..` 10, !IO),
print_line("", !IO),
print("With > as order predicate: ", !IO),
foldl(Print_kth_greatest, 1 `..` 10, !IO),
print_line("", !IO).
:- pred print_kth_least(int::in, list(int)::in,
M::in, io::di, io::uo)
is det <= urandom(M, io).
print_kth_least(K, Numbers_list, M, !IO) :-
(array.from_list(Numbers_list, Arr0)),
quickselect(<, K - 1, Arr0, _, Elem, M, !IO),
print(" ", !IO),
print(Elem, !IO).
:- pred print_kth_greatest(int::in, list(int)::in,
M::in, io::di, io::uo)
is det <= urandom(M, io).
print_kth_greatest(K, Numbers_list, M, !IO) :-
(array.from_list(Numbers_list, Arr0)),
%% Notice that the "Less_than" predicate is actually "greater
%% than". :) One can think of this as meaning that a greater number
%% has an *ordinal* that is "less than"; that is, it "comes before"
%% in the order.
quickselect(>, K - 1, Arr0, _, Elem, M, !IO),
print(" ", !IO),
print(Elem, !IO).
%%%-------------------------------------------------------------------
%%% local variables:
%%% mode: mercury
%%% prolog-indent-width: 2
%%% end:
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#NetRexx
|
NetRexx
|
/* NetRexx */
options replace format comments java crossref symbols nobinary
/** @see <a href="http://en.wikipedia.org/wiki/Quickselect">http://en.wikipedia.org/wiki/Quickselect</a> */
runSample(arg)
return
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
method qpartition(list, ileft, iright, pivotIndex) private static
pivotValue = list[pivotIndex]
list = swap(list, pivotIndex, iright) -- Move pivot to end
storeIndex = ileft
loop i_ = ileft to iright - 1
if list[i_] <= pivotValue then do
list = swap(list, storeIndex, i_)
storeIndex = storeIndex + 1
end
end i_
list = swap(list, iright, storeIndex) -- Move pivot to its final place
return storeIndex
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
method qselectInPlace(list, k_, ileft = -1, iright = -1) public static
if ileft = -1 then ileft = 1
if iright = -1 then iright = list[0]
loop label inplace forever
pivotIndex = Random().nextInt(iright - ileft + 1) + ileft -- select pivotIndex between left and right
pivotNewIndex = qpartition(list, ileft, iright, pivotIndex)
pivotDist = pivotNewIndex - ileft + 1
select
when pivotDist = k_ then do
returnVal = list[pivotNewIndex]
leave inplace
end
when k_ < pivotDist then
iright = pivotNewIndex - 1
otherwise do
k_ = k_ - pivotDist
ileft = pivotNewIndex + 1
end
end
end inplace
return returnVal
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
method swap(list, i1, i2) private static
if i1 \= i2 then do
t1 = list[i1]
list[i1] = list[i2]
list[i2] = t1
end
return list
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method runSample(arg) private static
parse arg samplelist
if samplelist = '' | samplelist = '.' then samplelist = 9 8 7 6 5 0 1 2 3 4
items = samplelist.words
say 'Input:'
say ' 'samplelist.space(1, ',').changestr(',', ', ')
say
say 'Using in-place version of the algorithm:'
iv = ''
loop k_ = 1 to items
iv = iv qselectInPlace(buildIndexedString(samplelist), k_)
end k_
say ' 'iv.space(1, ',').changestr(',', ', ')
say
say 'Find the 4 smallest:'
iv = ''
loop k_ = 1 to 4
iv = iv qselectInPlace(buildIndexedString(samplelist), k_)
end k_
say ' 'iv.space(1, ',').changestr(',', ', ')
say
say 'Find the 3 largest:'
iv = ''
loop k_ = items - 2 to items
iv = iv qselectInPlace(buildIndexedString(samplelist), k_)
end k_
say ' 'iv.space(1, ',').changestr(',', ', ')
say
return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method buildIndexedString(samplelist) private static
list = 0
list[0] = samplelist.words()
loop k_ = 1 to list[0]
list[k_] = samplelist.word(k_)
end k_
return list
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#Icon_and_Unicon
|
Icon and Unicon
|
procedure main()
R := [ 0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39 ]
write("Input list := ",list2string(R))
write("Extracted sting := ",s := range_extract(R) | "FAILED")
end
procedure range_extract(R) #: return string/range representation of a list of unique integers
local s,sep,low,high,x
every if integer(x:= !R) ~= x then fail # ensure all are integers,
R := sort(set(R)) # unique, and sorted
s := sep := ""
while s ||:= sep || ( low := high := get(R) ) do { # lower bound of range
sep := ","
while high := ( R[1] = high + 1 ) do get(R) # find the end of range
if high > low+1 then s ||:= "-" || high # - record range of 3+
else if high = low+1 then push(R,high) # - range of 2, high becomes new low
}
return s
end
procedure list2string(L) #: helper to convert list to string
local s
every (s := "[ ") ||:= !L || " "
return s || "]"
end
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Modula-3
|
Modula-3
|
MODULE Rand EXPORTS Main;
IMPORT Random;
FROM Math IMPORT log, cos, sqrt, Pi;
VAR rands: ARRAY [1..1000] OF LONGREAL;
(* Normal distribution. *)
PROCEDURE RandNorm(): LONGREAL =
BEGIN
WITH rand = NEW(Random.Default).init() DO
RETURN
sqrt(-2.0D0 * log(rand.longreal())) * cos(2.0D0 * Pi * rand.longreal());
END;
END RandNorm;
BEGIN
FOR i := FIRST(rands) TO LAST(rands) DO
rands[i] := 1.0D0 + 0.5D0 * RandNorm();
END;
END Rand.
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#Nanoquery
|
Nanoquery
|
list = {0} * 1000
mean = 1.0; std = 0.5
rng = new(Nanoquery.Util.Random)
for i in range(0, len(list) - 1)
list[i] = mean + std * rng.getGaussian()
end
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#Peloton
|
Peloton
|
* blank lines and lines beginning with # and ; should be ignored.
* an all uppercase word defines a configuration symbol
* no tail means a boolean true
* a tail including a comma means a list
* any other kind of tail is a string
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Maple
|
Maple
|
ExpandRanges := proc( s :: string )
uses StringTools;
local DoOne := proc( input )
uses StringTools;
local lo, hi, pos;
if IsDigit( input ) or input[ 1 ] = "-"
and IsDigit( input[ 2 .. -1 ] ) then
parse( input )
else
pos := Search( "--", input );
if pos > 0 then
lo := input[ 1 .. pos - 1 ];
hi := input[ 1 + pos .. -1 ];
elif input[ 1 ] = "-" then
pos := FirstFromLeft( "-", input[ 2 .. -1 ] );
if pos = 0 then
lo := input;
hi := lo
else
lo := input[ 1 .. pos ];
hi := input[ 2 + pos .. -1 ];
end if;
else
pos := FirstFromLeft( "-", input );
if pos = 0 then
error "incorrect syntax"
end if;
lo := input[ 1 .. pos - 1 ];
hi := input[ 1 + pos .. -1 ];
end if;
lo := parse( lo );
hi := parse( hi );
seq( lo .. hi )
end if
end proc:
map( DoOne, map( Trim, Split( s, "," ) ) )
end proc:
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#Mathematica.2FWolfram_Language
|
Mathematica/Wolfram Language
|
rangeexpand[ rng_ ] := Module[ { step1 },
step1 = StringSplit[StringReplacePart[rng,"S",StringPosition[ rng,DigitCharacter~~"-"] /. {x_,y_} -> {y,y}],","];
Flatten@ToExpression/@Quiet@StringReplace[step1,x__~~"S"~~y__->"Range["<>x<>","<>y<>"]"] ]
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Maxima
|
Maxima
|
/* Read a file and return a list of all lines */
readfile(name) := block(
[v: [ ], f: openr(name), line],
while stringp(line: readline(f)) do v: endcons(line, v),
close(f),
v
)$
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#Racket
|
Racket
|
#lang racket
(define (string-reverse s)
(list->string (reverse (string->list s))))
(string-reverse "aoeu")
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Delphi
|
Delphi
|
program QueueDefinition;
{$APPTYPE CONSOLE}
uses
System.Generics.Collections;
type
TQueue = System.Generics.Collections.TQueue<Integer>;
TQueueHelper = class helper for TQueue
function Empty: Boolean;
function Pop: Integer;
procedure Push(const NewItem: Integer);
end;
{ TQueueHelper }
function TQueueHelper.Empty: Boolean;
begin
Result := count = 0;
end;
function TQueueHelper.Pop: Integer;
begin
Result := Dequeue;
end;
procedure TQueueHelper.Push(const NewItem: Integer);
begin
Enqueue(NewItem);
end;
var
Queue: TQueue;
i: Integer;
begin
Queue := TQueue.Create;
for i := 1 to 1000 do
Queue.push(i);
while not Queue.Empty do
Write(Queue.pop, ' ');
Writeln;
Queue.Free;
Readln;
end.
|
http://rosettacode.org/wiki/Quaternion_type
|
Quaternion type
|
Quaternions are an extension of the idea of complex numbers.
A complex number has a real and complex part, sometimes written as a + bi,
where a and b stand for real numbers, and i stands for the square root of minus 1.
An example of a complex number might be -3 + 2i,
where the real part, a is -3.0 and the complex part, b is +2.0.
A quaternion has one real part and three imaginary parts, i, j, and k.
A quaternion might be written as a + bi + cj + dk.
In the quaternion numbering system:
i∙i = j∙j = k∙k = i∙j∙k = -1, or more simply,
ii = jj = kk = ijk = -1.
The order of multiplication is important, as, in general, for two quaternions:
q1 and q2: q1q2 ≠ q2q1.
An example of a quaternion might be 1 +2i +3j +4k
There is a list form of notation where just the numbers are shown and the imaginary multipliers i, j, and k are assumed by position.
So the example above would be written as (1, 2, 3, 4)
Task
Given the three quaternions and their components:
q = (1, 2, 3, 4) = (a, b, c, d)
q1 = (2, 3, 4, 5) = (a1, b1, c1, d1)
q2 = (3, 4, 5, 6) = (a2, b2, c2, d2)
And a wholly real number r = 7.
Create functions (or classes) to perform simple maths with quaternions including computing:
The norm of a quaternion:
=
a
2
+
b
2
+
c
2
+
d
2
{\displaystyle ={\sqrt {a^{2}+b^{2}+c^{2}+d^{2}}}}
The negative of a quaternion:
= (-a, -b, -c, -d)
The conjugate of a quaternion:
= ( a, -b, -c, -d)
Addition of a real number r and a quaternion q:
r + q = q + r = (a+r, b, c, d)
Addition of two quaternions:
q1 + q2 = (a1+a2, b1+b2, c1+c2, d1+d2)
Multiplication of a real number and a quaternion:
qr = rq = (ar, br, cr, dr)
Multiplication of two quaternions q1 and q2 is given by:
( a1a2 − b1b2 − c1c2 − d1d2,
a1b2 + b1a2 + c1d2 − d1c2,
a1c2 − b1d2 + c1a2 + d1b2,
a1d2 + b1c2 − c1b2 + d1a2 )
Show that, for the two quaternions q1 and q2:
q1q2 ≠ q2q1
If a language has built-in support for quaternions, then use it.
C.f.
Vector products
On Quaternions; or on a new System of Imaginaries in Algebra. By Sir William Rowan Hamilton LL.D, P.R.I.A., F.R.A.S., Hon. M. R. Soc. Ed. and Dub., Hon. or Corr. M. of the Royal or Imperial Academies of St. Petersburgh, Berlin, Turin and Paris, Member of the American Academy of Arts and Sciences, and of other Scientific Societies at Home and Abroad, Andrews' Prof. of Astronomy in the University of Dublin, and Royal Astronomer of Ireland.
|
#Forth
|
Forth
|
: quaternions 4 * floats ;
: qvariable create 1 quaternions allot ;
: q! ( a b c d q -- )
dup 3 floats + f! dup 2 floats + f! dup float+ f! f! ;
: qcopy ( src dest -- ) 1 quaternions move ;
: qnorm ( q -- f )
0e 4 0 do dup f@ fdup f* f+ float+ loop drop fsqrt ;
: qf* ( q f -- )
4 0 do dup f@ fover f* dup f! float+ loop fdrop drop ;
: qnegate ( q -- ) -1e qf* ;
: qconj ( q -- )
float+ 3 0 do dup f@ fnegate dup f! float+ loop drop ;
: qf+ ( q f -- ) dup f@ f+ f! ;
: q+ ( q1 q2 -- )
4 0 do over f@ dup f@ f+ dup f! float+ swap float+ swap loop 2drop ;
\ access
: q.a f@ ;
: q.b float+ f@ ;
: q.c 2 floats + f@ ;
: q.d 3 floats + f@ ;
: q* ( dest q1 q2 -- )
over q.a dup q.d f* over q.b dup q.c f* f+ over q.c dup q.b f* f- over q.d dup q.a f* f+
over q.a dup q.c f* over q.b dup q.d f* f- over q.c dup q.a f* f+ over q.d dup q.b f* f+
over q.a dup q.b f* over q.b dup q.a f* f+ over q.c dup q.d f* f+ over q.d dup q.c f* f-
over q.a dup q.a f* over q.b dup q.b f* f- over q.c dup q.c f* f- over q.d dup q.d f* f-
2drop 4 0 do dup f! float+ loop drop ;
: q= ( q1 q2 -- ? )
4 0 do
over f@ dup f@ f<> if 2drop false unloop exit then
float+ swap float+
loop
2drop true ;
\ testing
: q. ( q -- )
[char] ( emit space
4 0 do dup f@ f. float+ loop drop
[char] ) emit space ;
qvariable q 1e 2e 3e 4e q q!
qvariable q1 2e 3e 4e 5e q1 q!
create q2 3e f, 4e f, 5e f, 6e f, \ by hand
qvariable tmp
qvariable m1
qvariable m2
q qnorm f. \ 5.47722557505166
q tmp qcopy tmp qnegate tmp q. \ ( -1. -2. -3. -4. )
q tmp qcopy tmp qconj tmp q. \ ( 1. -2. -3. -4. )
q m1 qcopy m1 7e qf+ m1 q. \ ( 8. 2. 3. 4. )
q m2 qcopy 7e m2 qf+ m2 q. \ ( 8. 2. 3. 4. )
m1 m2 q= . \ -1 (true)
q2 tmp qcopy q1 tmp q+ tmp q. \ ( 5. 7. 9. 11. )
q m1 qcopy m1 7e qf* m1 q. \ ( 7. 14. 21. 28. )
q m2 qcopy 7e m2 qf* m2 q. \ ( 7. 14. 21. 28. )
m1 m2 q= . \ -1 (true)
m1 q1 q2 q* m1 q. \ ( -56. 16. 24. 26. )
m2 q2 q1 q* m2 q. \ ( -56. 18. 20. 28. )
m1 m2 q= . \ 0 (false)
|
http://rosettacode.org/wiki/Quine
|
Quine
|
A quine is a self-referential program that can,
without any external access, output its own source.
A quine (named after Willard Van Orman Quine) is also known as:
self-reproducing automata (1972)
self-replicating program or self-replicating computer program
self-reproducing program or self-reproducing computer program
self-copying program or self-copying computer program
It is named after the philosopher and logician
who studied self-reference and quoting in natural language,
as for example in the paradox "'Yields falsehood when preceded by its quotation' yields falsehood when preceded by its quotation."
"Source" has one of two meanings. It can refer to the text-based program source.
For languages in which program source is represented as a data structure, "source" may refer to the data structure: quines in these languages fall into two categories: programs which print a textual representation of themselves, or expressions which evaluate to a data structure which is equivalent to that expression.
The usual way to code a quine works similarly to this paradox: The program consists of two identical parts, once as plain code and once quoted in some way (for example, as a character string, or a literal data structure). The plain code then accesses the quoted code and prints it out twice, once unquoted and once with the proper quotation marks added. Often, the plain code and the quoted code have to be nested.
Task
Write a program that outputs its own source code in this way. If the language allows it, you may add a variant that accesses the code directly. You are not allowed to read any external files with the source code. The program should also contain some sort of self-reference, so constant expressions which return their own value which some top-level interpreter will print out. Empty programs producing no output are not allowed.
There are several difficulties that one runs into when writing a quine, mostly dealing with quoting:
Part of the code usually needs to be stored as a string or structural literal in the language, which needs to be quoted somehow. However, including quotation marks in the string literal itself would be troublesome because it requires them to be escaped, which then necessitates the escaping character (e.g. a backslash) in the string, which itself usually needs to be escaped, and so on.
Some languages have a function for getting the "source code representation" of a string (i.e. adds quotation marks, etc.); in these languages, this can be used to circumvent the quoting problem.
Another solution is to construct the quote character from its character code, without having to write the quote character itself. Then the character is inserted into the string at the appropriate places. The ASCII code for double-quote is 34, and for single-quote is 39.
Newlines in the program may have to be reproduced as newlines in the string, which usually requires some kind of escape sequence (e.g. "\n"). This causes the same problem as above, where the escaping character needs to itself be escaped, etc.
If the language has a way of getting the "source code representation", it usually handles the escaping of characters, so this is not a problem.
Some languages allow you to have a string literal that spans multiple lines, which embeds the newlines into the string without escaping.
Write the entire program on one line, for free-form languages (as you can see for some of the solutions here, they run off the edge of the screen), thus removing the need for newlines. However, this may be unacceptable as some languages require a newline at the end of the file; and otherwise it is still generally good style to have a newline at the end of a file. (The task is not clear on whether a newline is required at the end of the file.) Some languages have a print statement that appends a newline; which solves the newline-at-the-end issue; but others do not.
Next to the Quines presented here, many other versions can be found on the Quine page.
Related task
print itself.
|
#C.2B.2B
|
C++
|
#include<cstdio>
int main(){char n[]=R"(#include<cstdio>
int main(){char n[]=R"(%s%c";printf(n,n,41);})";printf(n,n,41);}
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#Oforth
|
Oforth
|
: testQueue
| q i |
Queue new ->q
20 loop: i [ i q push ]
while ( q empty not ) [ q pop . ] ;
|
http://rosettacode.org/wiki/Queue/Usage
|
Queue/Usage
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Create a queue data structure and demonstrate its operations.
(For implementations of queues, see the FIFO task.)
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#ooRexx
|
ooRexx
|
q = .queue~new -- create an instance
q~queue(3) -- adds to the end, but this is at the front
q~push(1) -- push on the front
q~queue(2) -- add to the end
say q~pull q~pull q~pull q~isempty -- should display all and be empty
|
http://rosettacode.org/wiki/Quickselect_algorithm
|
Quickselect algorithm
|
Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.
For comparing various sorts, see compare sorts.
For other sorting algorithms, see sorting algorithms, or:
O(n logn) sorts
Heap sort |
Merge sort |
Patience sort |
Quick sort
O(n log2n) sorts
Shell Sort
O(n2) sorts
Bubble sort |
Cocktail sort |
Cocktail sort with shifting bounds |
Comb sort |
Cycle sort |
Gnome sort |
Insertion sort |
Selection sort |
Strand sort
other sorts
Bead sort |
Bogo sort |
Common sorted list |
Composite structures sort |
Custom comparator sort |
Counting sort |
Disjoint sublist sort |
External sort |
Jort sort |
Lexicographical sort |
Natural sorting |
Order by pair comparisons |
Order disjoint list items |
Order two numerical lists |
Object identifier (OID) sort |
Pancake sort |
Quickselect |
Permutation sort |
Radix sort |
Ranking methods |
Remove duplicate elements |
Sleep sort |
Stooge sort |
[Sort letters of a string] |
Three variable sort |
Topological sort |
Tree sort
Use the quickselect algorithm on the vector
[9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
To show the first, second, third, ... up to the tenth largest member of the vector, in order, here on this page.
Note: Quicksort has a separate task.
|
#Nim
|
Nim
|
proc qselect[T](a: var openarray[T]; k: int, inl = 0, inr = -1): T =
var r = if inr >= 0: inr else: a.high
var st = 0
for i in 0 ..< r:
if a[i] > a[r]: continue
swap a[i], a[st]
inc st
swap a[r], a[st]
if k == st: a[st]
elif st > k: qselect(a, k, 0, st - 1)
else: qselect(a, k, st, inr)
let x = [9, 8, 7, 6, 5, 0, 1, 2, 3, 4]
for i in 0..9:
var y = x
echo i, ": ", qselect(y, i)
|
http://rosettacode.org/wiki/Range_extraction
|
Range extraction
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Create a function that takes a list of integers in increasing order and returns a correctly formatted string in the range format.
Use the function to compute and print the range formatted version of the following ordered list of integers. (The correct answer is: 0-2,4,6-8,11,12,14-25,27-33,35-39).
0, 1, 2, 4, 6, 7, 8, 11, 12, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
37, 38, 39
Show the output of your program.
Related task
Range expansion
|
#J
|
J
|
fmt=: [: ;@(8!:0) [`]`({. ; (',-' {~ 2 < #) ; {:)@.(2 <. #)
group=: <@fmt;.1~ 1 ~: 0 , 2 -~/\ ]
extractRange=: ',' joinstring group
|
http://rosettacode.org/wiki/Random_numbers
|
Random numbers
|
Task
Generate a collection filled with 1000 normally distributed random (or pseudo-random) numbers
with a mean of 1.0 and a standard deviation of 0.5
Many libraries only generate uniformly distributed random numbers. If so, you may use one of these algorithms.
Related task
Standard deviation
|
#NetRexx
|
NetRexx
|
/* NetRexx */
options replace format comments java crossref symbols nobinary
import java.math.BigDecimal
import java.math.MathContext
-- prologue
numeric digits 20
-- get input, set defaults
parse arg dp mu sigma ec .
if mu = '' | mu = '.' then mean = 1.0; else mean = mu
if sigma = '' | sigma = '.' then stdDeviation = 0.5; else stdDeviation = sigma
if dp = '' | dp = '.' then displayPrecision = 1; else displayPrecision = dp
if ec = '' | ec = '.' then elements = 1000; else elements = ec
-- set up
RNG = Random()
numberList = java.util.List
numberList = ArrayList()
-- generate list of random numbers
loop for elements
rn = mean + stdDeviation * RNG.nextGaussian()
numberList.add(BigDecimal(rn, MathContext.DECIMAL128))
end
-- report
say "Mean: " mean
say "Standard Deviation:" stdDeviation
say "Precision: " displayPrecision
say
drawBellCurve(numberList, displayPrecision)
return
-- -----------------------------------------------------------------------------
method drawBellCurve(numberList = java.util.List, precision) static
Collections.sort(numberList)
val = BigDecimal
lastN = ''
nextN = ''
loop val over numberList
nextN = Rexx(val.toPlainString()).format(5, precision)
select
when lastN = '' then nop
when lastN \= nextN then say lastN
otherwise nop
end
say '*\-'
lastN = nextN
end val
say lastN
return
|
http://rosettacode.org/wiki/Read_a_configuration_file
|
Read a configuration file
|
The task is to read a configuration file in standard configuration file format,
and set variables accordingly.
For this task, we have a configuration file as follows:
# This is a configuration file in standard configuration file format
#
# Lines beginning with a hash or a semicolon are ignored by the application
# program. Blank lines are also ignored by the application program.
# This is the fullname parameter
FULLNAME Foo Barber
# This is a favourite fruit
FAVOURITEFRUIT banana
# This is a boolean that should be set
NEEDSPEELING
# This boolean is commented out
; SEEDSREMOVED
# Configuration option names are not case sensitive, but configuration parameter
# data is case sensitive and may be preserved by the application program.
# An optional equals sign can be used to separate configuration parameter data
# from the option name. This is dropped by the parser.
# A configuration option may take multiple parameters separated by commas.
# Leading and trailing whitespace around parameter names and parameter data fields
# are ignored by the application program.
OTHERFAMILY Rhu Barber, Harry Barber
For the task we need to set four variables according to the configuration entries as follows:
fullname = Foo Barber
favouritefruit = banana
needspeeling = true
seedsremoved = false
We also have an option that contains multiple parameters. These may be stored in an array.
otherfamily(1) = Rhu Barber
otherfamily(2) = Harry Barber
Related tasks
Update a configuration file
|
#Perl
|
Perl
|
my $fullname;
my $favouritefruit;
my $needspeeling;
my $seedsremoved;
my @otherfamily;
# configuration file definition. See read_conf_file below for explanation.
my $conf_definition = {
'fullname' => [ 'string', \$fullname ],
'favouritefruit' => [ 'string', \$favouritefruit ],
'needspeeling' => [ 'boolean', \$needspeeling ],
'seedsremoved' => [ 'boolean', \$seedsremoved ],
'otherfamily' => [ 'array', \@otherfamily ],
};
my $arg = shift; # take the configuration file name from the command line
# (or first subroutine argument if this were in a sub)
my $file; # this is going to be a file handle reference
open $file, $arg or die "Can't open configuration file '$arg': $!";
read_conf_file($file, $conf_definition);
print "fullname = $fullname\n";
print "favouritefruit = $favouritefruit\n";
print "needspeeling = ", ($needspeeling ? 'true' : 'false'), "\n";
print "seedsremoved = ", ($seedsremoved ? 'true' : 'false'), "\n";
for (my $i = 0; $i < @otherfamily; ++$i) {
print "otherfamily(", $i + 1, ") = ", $otherfamily[$i], "\n";
}
# read_conf_file: Given a file handle opened for reading and a configuration definition,
# read the file.
# If the configuration file doesn't match the definition, raise an exception with "die".
# The configuration definition is (a reference to) an associative array
# where the keys are the configuration variable names in all lower case
# and the values are references to arrays.
# The first element of each of these arrays is the expected type: 'boolean', 'string', or 'array';
# the second element is a reference to the variable that should be assigned the data.
sub read_conf_file {
my ($fh, $def) = @_; # copy parameters
local $_; # avoid interfering with use of $_ in main program
while (<$fh>) { # read a line from $fh into $_ until end of file
next if /^#/; # skip "#" comments
next if /^;/; # skip ";" comments
next if /^$/; # skip blank lines
chomp; # strip final newline
$_ =~ /^\s*(\w+)\s*(.*)$/i or die "Syntax error";
my $key = $1;
my $rest = $2;
$key =~ tr/[A-Z]/[a-z]/; # convert keyword to lower case
if (!exists $def->{$key}) {
die "Unknown keyword: '$key'";
}
if ($def->{$key}[0] eq 'boolean') {
if ($rest) {
die "Syntax error: extra data following boolean '$key'";
}
${$def->{$key}[1]} = 1;
next; # done with this line, go back to "while"
}
$rest =~ s/\s*$//; # drop trailing whitespace
$rest =~ s/^=\s*//; # drop equals sign if present
if ($def->{$key}[0] eq 'string') {
${$def->{$key}[1]} = $rest;
} elsif ($def->{$key}[0] eq 'array') {
@{$def->{$key}[1]} = split /\s*,\s*/, $rest;
} else {
die "Internal error (unknown type in configuration definition)";
}
}
}
|
http://rosettacode.org/wiki/Range_expansion
|
Range expansion
|
A format for expressing an ordered list of integers is to use a comma separated list of either
individual integers
Or a range of integers denoted by the starting integer separated from the end integer in the range by a dash, '-'. (The range includes all integers in the interval including both endpoints)
The range syntax is to be used only for, and for every range that expands to more than two values.
Example
The list of integers:
-6, -3, -2, -1, 0, 1, 3, 4, 5, 7, 8, 9, 10, 11, 14, 15, 17, 18, 19, 20
Is accurately expressed by the range expression:
-6,-3-1,3-5,7-11,14,15,17-20
(And vice-versa).
Task
Expand the range description:
-6,-3--1,3-5,7-11,14,15,17-20
Note that the second element above,
is the range from minus 3 to minus 1.
Related task
Range extraction
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
function L=range_expansion(S)
% Range expansion
if nargin < 1;
S='[]';
end
if ~all(isdigit(S) | (S=='-') | (S==',') | isspace(S))
error 'invalid input';
end
ixr = find(isdigit(S(1:end-1)) & S(2:end) == '-')+1;
S(ixr)=':';
S=['[',S,']'];
L=eval(S);
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Mercury
|
Mercury
|
:- module read_a_file_line_by_line.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module int, list, require, string.
main(!IO) :-
io.open_input("test.txt", OpenResult, !IO),
(
OpenResult = ok(File),
read_file_line_by_line(File, 0, !IO)
;
OpenResult = error(Error),
error(io.error_message(Error))
).
:- pred read_file_line_by_line(io.text_input_stream::in, int::in,
io::di, io::uo) is det.
read_file_line_by_line(File, !.LineCount, !IO) :-
% We could also use io.read_line/3 which returns a list of characters
% instead of a string.
io.read_line_as_string(File, ReadLineResult, !IO),
(
ReadLineResult = ok(Line),
!:LineCount = !.LineCount + 1,
io.format("%d: %s", [i(!.LineCount), s(Line)], !IO),
read_file_line_by_line(File, !.LineCount, !IO)
;
ReadLineResult = eof
;
ReadLineResult = error(Error),
error(io.error_message(Error))
).
|
http://rosettacode.org/wiki/Read_a_file_line_by_line
|
Read a file line by line
|
Read a file one line at a time,
as opposed to reading the entire file at once.
Related tasks
Read a file character by character
Input loop.
|
#Neko
|
Neko
|
/**
Read a file line by line, in Neko
<doc><pre>Tectonics:
nekoc readfile.neko
neko readfile [filename]</pre></doc>
*/
var stdin = $loader.loadprim("std@file_stdin", 0)()
var file_open = $loader.loadprim("std@file_open", 2)
var file_read_char = $loader.loadprim("std@file_read_char", 1)
/* Read a line from file f into string s returning length without any newline */
var NEKO_MAX = 1 << 29
var strsize = 256
var NEWLINE = 10
var readline = function(f) {
var s = $smake(strsize)
var len = 0
var ch
var file_exception = false
while true {
try ch = file_read_char(f) catch problem { file_exception = problem; break; }
if ch == NEWLINE break;
if $sset(s, len, ch) == null break; else len += 1
if len == strsize - 1 {
strsize *= 2
if strsize > NEKO_MAX $throw("Out of string space for readline")
var t = s
s = $smake(strsize)
$sblit(s, 0, t, 0, $ssize(t))
}
}
if $istrue(file_exception) $rethrow(file_exception)
return $ssub(s, 0, len)
}
var infile
var cli = $loader.args[0]
if cli == null infile = stdin
else {
cli = $string(cli)
try infile = file_open(cli, "r")
catch problem $print(problem, " Can't open ", cli, "\n")
}
if infile == null $throw("Can't open " + cli)
var str
while true {
try {
str = readline(infile)
$print(":", str, ":\n")
} catch a break;
}
|
http://rosettacode.org/wiki/Reverse_a_string
|
Reverse a string
|
Task
Take a string and reverse it.
For example, "asdf" becomes "fdsa".
Extra credit
Preserve Unicode combining characters.
For example, "as⃝df̅" becomes "f̅ds⃝a", not "̅fd⃝sa".
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
|
#Raku
|
Raku
|
say "hello world".flip;
say "as⃝df̅".flip;
say 'ℵΑΩ 駱駝道 🤔 🇸🇧 🇺🇸 🇬🇧 👨👩👧👦🆗🗺'.flip;
|
http://rosettacode.org/wiki/Queue/Definition
|
Queue/Definition
|
Data Structure
This illustrates a data structure, a means of storing data within a program.
You may see other such structures in the Data Structures category.
Illustration of FIFO behavior
Task
Implement a FIFO queue.
Elements are added at one side and popped from the other in the order of insertion.
Operations:
push (aka enqueue) - add element
pop (aka dequeue) - pop first element
empty - return truth value when empty
Errors:
handle the error of trying to pop from an empty queue (behavior depends on the language and platform)
See
Queue/Usage for the built-in FIFO or queue of your language or standard library.
See also
Array
Associative array: Creation, Iteration
Collections
Compound data type
Doubly-linked list: Definition, Element definition, Element insertion, List Traversal, Element Removal
Linked list
Queue: Definition, Usage
Set
Singly-linked list: Element definition, Element insertion, List Traversal, Element Removal
Stack
|
#E
|
E
|
def makeQueue() {
def [var head, var tail] := Ref.promise()
def writer {
to enqueue(value) {
def [nh, nt] := Ref.promise()
tail.resolve([value, nh])
tail := nt
}
}
def reader {
to empty() { return !Ref.isResolved(head) }
to dequeue(whenEmpty) {
if (Ref.isResolved(head)) {
def [value, next] := head
head := next
return value
} else {
throw.eject(whenEmpty, "pop() of empty queue")
}
}
}
return [reader, writer]
}
|
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