task_url
stringlengths 30
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| task_name
stringlengths 2
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| task_description
stringlengths 0
14.4k
| language_url
stringlengths 2
53
| language_name
stringlengths 1
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stringlengths 0
61.9k
|
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#ScratchScript
|
ScratchScript
|
pos -100 70
print "Goodbye, World!"
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
include "draw.s7i";
include "keybd.s7i";
include "bitmapfont.s7i";
include "stdfont24.s7i";
include "pixmap_file.s7i";
const proc: main is func
local
var text: screen is STD_NULL;
begin
screen(400, 100);
clear(curr_win, white);
KEYBOARD := GRAPH_KEYBOARD;
screen := openPixmapFontFile(curr_win);
color(screen, black, white);
setFont(screen, stdFont24);
setPosXY(screen, 68, 60);
write(screen, "Goodbye, World");
ignore(getc(KEYBOARD));
end func;
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Scala
|
Scala
|
def encode(n: Int) = (n ^ (n >>> 1)).toBinaryString
def decode(s: String) = Integer.parseInt( s.scanLeft(0)(_ ^ _.asDigit).tail.mkString , 2)
println("decimal binary gray decoded")
for (i <- 0 to 31; g = encode(i))
println("%7d %6s %5s %7s".format(i, i.toBinaryString, g, decode(g)))
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Scratch
|
Scratch
|
$ include "seed7_05.s7i";
include "bin32.s7i";
const func integer: grayEncode (in integer: n) is
return ord(bin32(n) >< bin32(n >> 1));
const func integer: grayDecode (in var integer: n) is func
result
var integer: decoded is 0;
begin
decoded := n;
while n > 1 do
n >>:= 1;
decoded := ord(bin32(decoded) >< bin32(n));
end while;
end func;
const proc: main is func
local
var integer: i is 0;
begin
for i range 0 to 32 do
writeln(i <& " => " <& grayEncode(i) radix 2 lpad0 6 <& " => " <& grayDecode(grayEncode(i)));
end for;
end func;
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#dc
|
dc
|
1 2 SaSbLaLb f
=2 1
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#E
|
E
|
pragma.enable("accumulator") # non-finalized syntax feature
def max([first] + rest) {
return accum first for x in rest { _.max(x) }
}
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#D
|
D
|
import std.stdio, std.numeric;
long myGCD(in long x, in long y) pure nothrow @nogc {
if (y == 0)
return x;
return myGCD(y, x % y);
}
void main() {
gcd(15, 10).writeln; // From Phobos.
myGCD(15, 10).writeln;
}
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Eiffel
|
Eiffel
|
class
APPLICATION
create
make
feature
make
local
test: LINKED_LIST [INTEGER]
count, number, te: INTEGER
do
create test.make
test := hailstone_sequence (27)
io.put_string ("There are " + test.count.out + " elements in the sequence for the number 27.")
io.put_string ("%NThe first 4 elements are: ")
across
1 |..| 4 as t
loop
io.put_string (test [t.item].out + "%T")
end
io.put_string ("%NThe last 4 elements are: ")
across
(test.count - 3) |..| test.count as t
loop
io.put_string (test [t.item].out + "%T")
end
across
1 |..| 99999 as c
loop
test := hailstone_sequence (c.item)
te := test.count
if te > count then
count := te
number := c.item
end
end
io.put_string ("%NThe longest sequence for numbers below 100000 is " + count.out + " for the number " + number.out + ".")
end
hailstone_sequence (n: INTEGER): LINKED_LIST [INTEGER]
-- Members of the Hailstone Sequence starting from 'n'.
require
n_is_positive: n > 0
local
seq: INTEGER
do
create Result.make
from
seq := n
until
seq = 1
loop
Result.extend (seq)
if seq \\ 2 = 0 then
seq := seq // 2
else
seq := ((3 * seq) + 1)
end
end
Result.extend (seq)
ensure
sequence_terminated: Result.last = 1
end
end
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#Picat
|
Picat
|
go =>
println([hamming(I) : I in 1..20]),
time(println(hamming_1691=hamming(1691))),
time(println(hamming_1000000=hamming(1000000))),
nl.
hamming(1) = 1.
hamming(2) = 2.
hamming(3) = 3.
hamming(N) = Hamming =>
A = new_array(N),
[Next2, Next3, Next5] = [2,3,5],
A[1] := Next2, A[2] := Next3, A[3] := Next5,
I = 0, J = 0, K = 0, M = 1,
while (M < N)
A[M] := min([Next2,Next3,Next5]),
if A[M] == Next2 then I := I+1, Next2 := 2*A[I] end,
if A[M] == Next3 then J := J+1, Next3 := 3*A[J] end,
if A[M] == Next5 then K := K+1, Next5 := 5*A[K] end,
M := M + 1
end,
Hamming = A[N-1].
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Ring
|
Ring
|
### Bert Mariani
### 2018-03-01
### Guess_My_Number
myNumber = random(10)
answer = 0
See "Guess my number between 1 and 10"+ nl
while answer != myNumber
See "Your guess: "
Give answer
if answer = myNumber
See "Well done! You guessed it! "+ myNumber +nl
else
See "Try again"+ nl
ok
if answer = 0
See "Give up. My number is: "+ myNumber +nl
ok
end
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#RPL
|
RPL
|
DIR
INITIALIZE
<< { C G R } PURGE RAND 10 * 1 + IP 'R' STO GUESSING
>>
GUESSING
<< "Pick a number between 1 and 10." "" INPUT OBJ-> 'G' STO
IF
G R ==
THEN
CLLCD "You got it!" 1 DISP 7 FREEZE 0 WAIT CLLCD CONTINUE
ELSE
IF
G R <
THEN
CLLCD "Try a larger number." 1 DISP 7 FREEZE 0 WAIT GUESSING
ELSE
CLLCD "Try a smaller number." 1 DISP 7 FREEZE 0 WAIT GUESSING
END
END
>>
CONTINUE
<< "Do you want to continue? (0/1)" "" INPUT OBJ-> 'C' STO
IF
C 1 ==
THEN
INITIALIZE
ELSE
CLEAR
END
>>
END
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#Tcl
|
Tcl
|
package require Tcl 8.5
set a {-1 -2 3 5 6 -2 -1 4 -4 2 -1}
# from the Perl solution
proc maxsumseq1 {a} {
set len [llength $a]
set maxsum 0
for {set start 0} {$start < $len} {incr start} {
for {set end $start} {$end < $len} {incr end} {
set sum 0
incr sum [expr [join [lrange $a $start $end] +]]
if {$sum > $maxsum} {
set maxsum $sum
set maxsumseq [lrange $a $start $end]
}
}
}
return $maxsumseq
}
# from the Python solution
proc maxsumseq2 {sequence} {
set start -1
set end -1
set maxsum_ 0
set sum_ 0
for {set i 0} {$i < [llength $sequence]} {incr i} {
set x [lindex $sequence $i]
incr sum_ $x
if {$maxsum_ < $sum_} {
set maxsum_ $sum_
set end $i
} elseif {$sum_ < 0} {
set sum_ 0
set start $i
}
}
assert {$maxsum_ == [maxsum $sequence]}
assert {$maxsum_ == [sum [lrange $sequence [expr {$start + 1}] $end]]}
return [lrange $sequence [expr {$start + 1}] $end]
}
proc maxsum {sequence} {
set maxsofar 0
set maxendinghere 0
foreach x $sequence {
set maxendinghere [expr {max($maxendinghere + $x, 0)}]
set maxsofar [expr {max($maxsofar, $maxendinghere)}]
}
return $maxsofar
}
proc assert {condition {message "Assertion failed!"}} {
if { ! [uplevel 1 [list expr $condition]]} {
return -code error $message
}
}
proc sum list {
expr [join $list +]
}
puts "sequence: $a"
puts "maxsumseq1: [maxsumseq1 $a]"
puts [time {maxsumseq1 $a} 1000]
puts "maxsumseq2: [maxsumseq2 $a]"
puts [time {maxsumseq2 $a} 1000]
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
function guess_a_number(low, high)
if nargin < 1 || ~isnumeric(low) || length(low) > 1 || isnan(low)
low = 1;
end;
if nargin < 2 || ~isnumeric(high) || length(high) > 1 || isnan(high)
high = low+9;
elseif low > high
[low, high] = deal(high, low);
end
n = floor(rand(1)*(high-low+1))+low;
gs = input(sprintf('Guess an integer between %i and %i (inclusive): ', low, high), 's');
while gs % No guess quits the game
g = str2double(gs);
if length(g) > 1 || isnan(g) || g < low || g > high
gs = input('Invalid input, guess again: ', 's');
elseif g < n
gs = input('Too low, guess again: ', 's');
elseif g > n
gs = input('Too high, guess again: ', 's');
else
disp('Good job, you win!')
gs = '';
end
end
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#ML
|
ML
|
(*
A happy number is defined by the following process. Starting with any positive integer, replace the number
by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will
stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends
in 1 are happy numbers, while those that do not end in 1 are unhappy numbers. Display an example of your
output here.
*)
local
fun get_digits
(d, s) where (d = 0) = s
| (d, s) = get_digits( d div 10, (d mod 10) :: s)
| n = get_digits( n div 10, [n mod 10] )
;
fun mem
(x, []) = false
| (x, a :: as) where (x = a) = true
| (x, _ :: as) = mem (x, as)
in
fun happy
1 = "happy"
| n =
let
val this = (fold (+,0) ` map (fn n = n ^ 2) ` get_digits n);
val sads = [2, 4, 16, 37, 58, 89, 145, 42, 20]
in
if (mem (n,sads)) then
"unhappy"
else
happy this
end
end
;
foreach (fn n = (print n; print " is "; println ` happy n)) ` iota 10;
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Jacquard_Loom
|
Jacquard Loom
|
+---------------+
| |
| * * |
|* * * * |
|* * *|
|* * *|
|* * * |
| * * * |
| * |
+---------------+
+---------------+
| |
|* * * |
|* * * |
| * *|
| * *|
|* * * |
|* * * * |
| * |
+---------------+
+---------------+
| |
|* ** * * |
|******* *** * |
| **** * * ***|
| **** * ******|
| ****** ** * |
| * * * * |
| * |
+---------------+
+---------------+
| |
|******* *** * |
|******* *** * |
| ** *|
|* * * *|
|******* ** * |
|******* *** * |
| * |
+---------------+
+---------------+
| |
|******* *** * |
|******* *** * |
| * * * *|
| * * * *|
|******* ** * |
|******* ** * |
| * |
+---------------+
+---------------+
| |
|***** * *** * |
|******* *** * |
| * * * * |
| * * * |
|****** ** * |
|****** ** * |
| * |
+---------------+
+---------------+
| |
| * * * |
|***** * ***** |
|***** ** * ***|
|***** ** * ***|
|******* * ** |
| * * * * |
| * |
+---------------+
+---------------+
| |
| |
| * * |
| * * |
| * |
| * |
| |
| |
+---------------+
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#SenseTalk
|
SenseTalk
|
Answer "Good Bye"
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Sidef
|
Sidef
|
var tk = require('Tk');
var main = %s'MainWindow'.new;
main.Button(
'-text' => 'Goodbye, World!',
'-command' => 'exit',
).pack;
tk.MainLoop;
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
include "bin32.s7i";
const func integer: grayEncode (in integer: n) is
return ord(bin32(n) >< bin32(n >> 1));
const func integer: grayDecode (in var integer: n) is func
result
var integer: decoded is 0;
begin
decoded := n;
while n > 1 do
n >>:= 1;
decoded := ord(bin32(decoded) >< bin32(n));
end while;
end func;
const proc: main is func
local
var integer: i is 0;
begin
for i range 0 to 32 do
writeln(i <& " => " <& grayEncode(i) radix 2 lpad0 6 <& " => " <& grayDecode(grayEncode(i)));
end for;
end func;
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#SenseTalk
|
SenseTalk
|
function BinaryToGray param1
set theResult to ""
repeat for each character in param1
if the counter is equal to 1
put it after theResult
else
if it is equal to previousCharacter
put "0" after theResult
else
put "1" after theResult
end if
end if
set previousCharacter to it
end repeat
return theResult
end BinaryToGray
function GrayToBinary param1
set theResult to param1
repeat for each character in param1
if the counter is equal to 1
next repeat
end if
set currentChar to it
set lastCharInd to the counter - 1
repeat for lastCharInd down to 1
if currentChar is equal to character it of param1
set currentChar to "0"
else
set currentChar to "1"
end if
end repeat
set character the counter of theResult to currentChar
end repeat
return theResult
end GrayToBinary
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#DCL
|
DCL
|
$ a1 = 123
$ a2 = "hello"
$ show symbol a*
$ gosub swap
$ show symbol a*
$ exit
$
$ swap:
$ t = a1
$ a1 = a2
$ a2 = t
$ return
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#EasyLang
|
EasyLang
|
a[] = [ 2 9 4 3 8 5 ]
for e in a[]
max = higher e max
.
print max
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#EchoLisp
|
EchoLisp
|
;; a random length list of random values
(define L (map random (make-list (random 50) 100))) → L
L → (24 60 83 8 24 60 31 97 96 65 9 41 64 24 22 57 73 17 6 28 77 58 18 13 27 22 41 69 85)
;; find max
(apply max L) → 97
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#Dc
|
Dc
|
[dSa%Lard0<G]dsGx+
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Elena
|
Elena
|
import system'collections;
import extensions;
const int maxNumber = 100000;
Hailstone(int n,Map<int,int> lengths)
{
if (n == 1)
{
^ 1
};
while (true)
{
if (lengths.containsKey(n))
{
^ lengths[n]
}
else
{
if (n.isEven())
{
lengths[n] := 1 + Hailstone(n/2, lengths)
}
else
{
lengths[n] := 1 + Hailstone(3*n + 1, lengths)
}
}
}
}
public program()
{
int longestChain := 0;
int longestNumber := 0;
auto recursiveLengths := new Map<int,int>(4096,4096);
for(int i := 1, i < maxNumber, i+=1)
{
var chainLength := Hailstone(i, recursiveLengths);
if (longestChain < chainLength)
{
longestChain := chainLength;
longestNumber := i
}
};
console.printFormatted("max below {0}: {1} ({2} steps)", maxNumber, longestNumber, longestChain)
}
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#PicoLisp
|
PicoLisp
|
(de hamming (N)
(let (L (1) H)
(do N
(for (X L X (cadr X)) # Find smallest result
(setq H (car X)) )
(idx 'L H NIL) # Remove it
(for I (2 3 5) # Generate next results
(idx 'L (* I H) T) ) )
H ) )
(println (make (for N 20 (link (hamming N)))))
(println (hamming 1691)) # very fast
(println (hamming 1000000)) # runtime about 13 minutes on i5-3570S
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Ruby
|
Ruby
|
n = rand(1..10)
puts 'Guess the number: '
puts 'Wrong! Guess again: ' until gets.to_i == n
puts 'Well guessed!'
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Run_BASIC
|
Run BASIC
|
while 1
choose = int(RND(0) * 9) + 1
while guess <> choose
print "Guess a number between 1 and 10: ";: input guess
if guess = choose THEN
print "You guessed!"
else
print "Sorry, try again"
end if
wend
wend
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#Ursala
|
Ursala
|
#import std
#import int
max_subsequence = zleq$^l&r/&+ *aayK33PfatPRTaq ^/~& sum:-0
#cast %zL
example = max_subsequence <-1,-2,3,5,6,-2,-1,4,-4,2,-1>
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#XPL0
|
XPL0
|
include c:\cxpl\codes;
int Array, Size, Sum, Best, I, Lo, Hi, BLo, BHi;
[Array:= [-1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1];
Size:= 11;
Best:= -100000;
for Lo:= 0 to Size-1 do
for Hi:= Lo to Size-1 do
[Sum:= 0;
for I:= Lo to Hi do
Sum:= Sum + Array(I);
if Sum > Best then
[Best:= Sum; BLo:= Lo; BHi:= Hi];
];
Text(0, "Sequence = ");
for I:= 0 to Size-1 do
[IntOut(0, Array(I)); Text(0, " ")];
CrLf(0);
Text(0, "Greatest = ");
for I:= BLo to BHi do
[IntOut(0, Array(I)); Text(0, " ")];
CrLf(0);
Text(0, "Sum = "); IntOut(0, Best); CrLf(0);
]
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#MAXScript
|
MAXScript
|
Range = [1,100]
randomNumber = (random Range.x Range.y) as integer
clearListener()
while true do
(
userVal = getKBValue prompt:("Enter a number between "+(range[1] as integer) as string+" and "+(range[2] as integer) as string+": ")
if userVal == randomNumber do (format "\nWell guessed!\n"; exit with OK)
case of
(
(classOf userVal != classof randomNumber): (format "\nBad number!\n")
(userVal > Range[2] or userVal < Range[1]): (format "\nNumber out of range\n")
(userVal > randomNumber): (format "\nToo high!\n")
(userVal < randomNumber): (format "\nToo low!\n")
)
)
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#Mirah
|
Mirah
|
def getInput:int
s = System.console.readLine()
Integer.parseInt(s)
end
number = int(Math.random() * 10 + 1)
puts "Guess the number between 1 and 10"
guessed = false
while !guessed do
begin
userNumber = getInput
if userNumber == number
guessed = true
puts "You guessed it."
elsif userNumber > number
puts "Too high."
else
puts "Too low."
end
rescue NumberFormatException => e
puts "Please enter an integer."
end
end
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#Modula-2
|
Modula-2
|
MODULE HappyNumbers;
FROM InOut IMPORT WriteCard, WriteLn;
CONST Amount = 8;
VAR seen, num: CARDINAL;
PROCEDURE SumDigitSquares(n: CARDINAL): CARDINAL;
VAR sum, digit: CARDINAL;
BEGIN
sum := 0;
WHILE n>0 DO
digit := n MOD 10;
n := n DIV 10;
sum := sum + digit * digit;
END;
RETURN sum;
END SumDigitSquares;
PROCEDURE Happy(n: CARDINAL): BOOLEAN;
VAR i: CARDINAL;
seen: ARRAY [0..255] OF BOOLEAN;
BEGIN
FOR i := 0 TO 255 DO
seen[i] := FALSE;
END;
REPEAT
seen[n] := TRUE;
n := SumDigitSquares(n);
UNTIL seen[n];
RETURN seen[1];
END Happy;
BEGIN
seen := 0;
num := 0;
WHILE seen < Amount DO
IF Happy(num) THEN
INC(seen);
WriteCard(num,2);
WriteLn();
END;
INC(num);
END;
END HappyNumbers.
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Java
|
Java
|
public class HelloWorld
{
public static void main(String[] args)
{
System.out.println("Hello world!");
}
}
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Smalltalk
|
Smalltalk
|
MessageBox show: 'Goodbye, world.'
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#SmileBASIC
|
SmileBASIC
|
DIALOG "Goodbye, world."
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Sidef
|
Sidef
|
func bin2gray(n) {
n ^ (n >> 1)
}
func gray2bin(num) {
var bin = num
while (num >>= 1) { bin ^= num }
return bin
}
{ |i|
var gr = bin2gray(i)
printf("%d\t%b\t%b\t%b\n", i, i, gr, gray2bin(gr))
} << ^32
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#SQL
|
SQL
|
DECLARE @BINARY AS NVARCHAR(MAX) = '001010111'
DECLARE @gray AS NVARCHAR(MAX) = ''
--Encoder
SET @gray = LEFT(@BINARY, 1)
WHILE LEN(@BINARY) > 1
BEGIN
IF LEFT(@BINARY, 1) != SUBSTRING(@BINARY, 2, 1)
SET @gray = @gray + '1'
ELSE
SET @gray = @gray + '0'
SET @BINARY = RIGHT(@BINARY, LEN(@BINARY) - 1)
END
SELECT @gray
--Decoder
SET @BINARY = LEFT(@gray, 1)
WHILE LEN(@gray) > 1
BEGIN
IF RIGHT(@BINARY, 1) != SUBSTRING(@gray, 2, 1)
SET @BINARY = @BINARY + '1'
ELSE
SET @BINARY = @BINARY + '0'
SET @gray = RIGHT(@gray, LEN(@gray) - 1)
END
SELECT @BINARY
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#Delphi
|
Delphi
|
procedure Swap_T(var a, b: T);
var
temp: T;
begin
temp := a;
a := b;
b := temp;
end;
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#ECL
|
ECL
|
MaxVal(SET OF INTEGER s) := MAX(s);
//example usage
SetVals := [4,8,16,2,1];
MaxVal(SetVals) //returns 16;
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Efene
|
Efene
|
list_max = fn ([Head:Rest]) {
list_max(Rest, Head)
}
list_max = fn ([], Res) {
Res
}
fn ([Head:Rest], Max) when Head > Max {
list_max(Rest, Head)
}
fn ([_Head:Rest], Max) {
list_max(Rest, Max)
}
list_max1 = fn ([H:T]) {
lists.foldl(fn erlang.max:2, H, T)
}
@public
run = fn () {
io.format("~p~n", [list_max([9, 4, 3, 8, 5])])
io.format("~p~n", [list_max1([9, 4, 3, 8, 5])])
}
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#Delphi
|
Delphi
|
proc nonrec gcd(word m, n) word:
word t;
while n ~= 0 do
t := m;
m := n;
n := t % n
od;
m
corp
proc nonrec show(word m, n) void:
writeln("gcd(", m, ", ", n, ") = ", gcd(m, n))
corp
proc nonrec main() void:
show(18, 12);
show(1071, 1029);
show(3528, 3780)
corp
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Elixir
|
Elixir
|
defmodule Hailstone do
require Integer
def step(1) , do: 0
def step(n) when Integer.is_even(n), do: div(n,2)
def step(n) , do: n*3 + 1
def sequence(n) do
Stream.iterate(n, &step/1) |> Stream.take_while(&(&1 > 0)) |> Enum.to_list
end
def run do
seq27 = sequence(27)
len27 = length(seq27)
repr = String.replace(inspect(seq27, limit: 4) <> inspect(Enum.drop(seq27,len27-4)), "][", ", ")
IO.puts "Hailstone(27) has #{len27} elements: #{repr}"
{len, start} = Enum.map(1..100_000, fn(n) -> {length(sequence(n)), n} end) |> Enum.max
IO.puts "Longest sequence starting under 100000 begins with #{start} and has #{len} elements."
end
end
Hailstone.run
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#PL.2FI
|
PL/I
|
(subscriptrange):
Hamming: procedure options (main); /* 14 November 2013 with fixes 2021 */
declare (H(2000), p2, p3, p5, twoTo31, Hm, tenP(11)) decimal(12)fixed;
declare (i, j, k, m, d, w) fixed binary;
/* Quicksorts in-place the array of integers H, from lb to ub */
quicksortH: procedure( lb, ub ) recursive;
declare ( lb, ub )binary(15)fixed;
declare ( left, right )binary(15)fixed;
declare ( pivot, swap )decimal(12)fixed;
declare sorting bit(1);
if ub > lb then do
/* more than one element, so must sort */
left = lb;
right = ub;
/* choosing the middle element of the array as the pivot */
pivot = H( left + ( ( right + 1 ) - left ) / 2 );
sorting = '1'b;
do while( sorting );
do while( left <= ub & H( left ) < pivot ); left = left + 1; end;
do while( right >= lb & H( right ) > pivot ); right = right - 1; end;
sorting = ( left <= right );
if sorting then do;
swap = H( left );
H( left ) = H( right );
H( right ) = swap;
left = left + 1;
right = right - 1;
end;
end;
call quicksortH( lb, right );
call quicksortH( left, ub );
end;
end quicksortH ;
/* find 2^31 - the limit for Hamming numbers we need to find */
twoTo31 = 2;
do i = 2 to 31;
twoTo31 = twoTo31 * 2;
end;
/* calculate powers of 10 so we can check the number of digits */
/* the numbers will have */
tenP( 1 ) = 10;
do i = 2 to 11;
tenP( i ) = 10 * tenP( i - 1 );
end;
/* find the numbers */
m = 0;
p5 = 1;
do k = 0 to 13;
p3 = 1;
do j = 0 to 19;
Hm = 0;
p2 = 1;
do i = 0 to 31 while( Hm < twoTo31 );
/* count the number of digits p2 * p3 * p5 will have */
d = 0;
do w = 1 to 11 while( tenP(w) < p2 ); d = d + 1; end;
do w = 1 to 11 while( tenP(w) < p3 ); d = d + 1; end;
do w = 1 to 11 while( tenP(w) < p5 ); d = d + 1; end;
if d < 11 then do;
/* the product will be small enough */
Hm = p2 * p3 * p5;
if Hm < twoTo31 then do;
m = m + 1;
H(m) = Hm;
end;
end;
p2 = p2 * 2;
end;
p3 = p3 * 3;
end;
p5 = p5 * 5;
end;
/* sort the numbers */
call quicksortH( 1, m );
put skip list( 'The first 20 Hamming numbers:' );
do i = 1 to 20;
put skip list (H(i));
end;
put skip list( 'Hamming number 1691:' );
put skip list (H(1691));
end Hamming;
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Rust
|
Rust
|
extern crate rand;
fn main() {
println!("Type in an integer between 1 and 10 and press enter.");
let n = rand::random::<u32>() % 10 + 1;
loop {
let mut line = String::new();
std::io::stdin().read_line(&mut line).unwrap();
let option: Result<u32,_> = line.trim().parse();
match option {
Ok(guess) => {
if guess < 1 || guess > 10 {
println!("Guess is out of bounds; try again.");
} else if guess == n {
println!("Well guessed!");
break;
} else {
println!("Wrong! Try again.");
}
},
Err(_) => println!("Invalid input; try again.")
}
}
}
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Scala
|
Scala
|
val n = (math.random * 10 + 1).toInt
print("Guess the number: ")
while(readInt != n) print("Wrong! Guess again: ")
println("Well guessed!")
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#Wren
|
Wren
|
var gss = Fn.new { |s|
var best = 0
var start = 0
var end = 0
var sum = 0
var sumStart = 0
var i = 0
for (x in s) {
sum = sum + x
if (sum > best) {
best = sum
start = sumStart
end = i + 1
} else if (sum < 0) {
sum = 0
sumStart = i + 1
}
i = i + 1
}
return [s[start...end], best]
}
var tests = [
[-1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1],
[-1, 1, 2, -5, -6],
[],
[-1, -2, -1]
]
for (test in tests) {
System.print("Input: %(test)")
var res = gss.call(test)
var subSeq = res[0]
var sum = res[1]
System.print("Sub seq: %(subSeq)")
System.print("Sum: %(sum)\n")
}
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#Modula-2
|
Modula-2
|
MODULE guessf;
IMPORT InOut, Random, NumConv, Strings;
VAR number, guess : CARDINAL;
input : Strings.String;
OK, Done : BOOLEAN;
BEGIN
number := Random.nr (1000);
InOut.WriteString ("I have chosen a number below 1000; please try to guess it.");
InOut.WriteLn;
REPEAT
REPEAT
InOut.WriteString ("Enter your guess : "); InOut.WriteBf;
InOut.ReadString (input);
NumConv.Str2Num (guess, 10, input, OK);
IF NOT OK THEN
InOut.WriteString (input);
InOut.WriteString (" is not a valid number...");
InOut.WriteLn
END
UNTIL OK;
InOut.WriteString ("Your guess is ");
IF number = guess THEN
Done := TRUE;
InOut.WriteString ("spot on!")
ELSE
Done := FALSE;
IF guess > number THEN
InOut.WriteString ("too high.")
ELSE
InOut.WriteString ("too low.")
END
END;
InOut.WriteLn
UNTIL Done;
InOut.WriteString ("Thank you for playing; have a nice day!");
InOut.WriteLn
END guessf.
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#MUMPS
|
MUMPS
|
ISHAPPY(N)
;Determines if a number N is a happy number
;Note that the returned strings do not have a leading digit unless it is a happy number
IF (N'=N\1)!(N<0) QUIT "Not a positive integer"
NEW SUM,I
;SUM is the sum of the square of each digit
;I is a loop variable
;SEQ is the sequence of previously checked SUMs from the original N
;If it isn't set already, initialize it to an empty string
IF $DATA(SEQ)=0 NEW SEQ SET SEQ=""
SET SUM=0
FOR I=1:1:$LENGTH(N) DO
.SET SUM=SUM+($EXTRACT(N,I)*$EXTRACT(N,I))
QUIT:(SUM=1) SUM
QUIT:$FIND(SEQ,SUM)>1 "Part of a sequence not containing 1"
SET SEQ=SEQ_","_SUM
QUIT $$ISHAPPY(SUM)
HAPPY(C) ;Finds the first C happy numbers
NEW I
;I is a counter for what integer we're looking at
WRITE !,"The first "_C_" happy numbers are:"
FOR I=1:1 QUIT:C<1 SET Q=+$$ISHAPPY(I) WRITE:Q !,I SET:Q C=C-1
KILL I
QUIT
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#JavaScript
|
JavaScript
|
document.write("Hello world!");
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#SSEM
|
SSEM
|
01100000000001110000000000000000
10000000000001010000000000000000
10011101110111011101010111000000
10010101010101010101010101000000
10010101010101010101010111000000
10011101110111011100110100000010
10000000000000000000010011000010
10011000000000000000100000000100
01101000000000000001000000000000
00000000000000000000000000000000
00000000000000000000000000000000
00100100100000000010000100100000
00100100100000000010000100100000
00100100101110111010011100100000
00100100101010100010010100100000
00100100101010100010010100000000
00100100101110100011011100100000
00011011000000000000000000000000
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Standard_ML
|
Standard ML
|
open XWindows ;
open Motif ;
val helloWindow = fn () =>
let
val shell = XtAppInitialise "" "demo" "top" [] [XmNwidth 400, XmNheight 300 ] ;
val main = XmCreateMainWindow shell "main" [XmNmappedWhenManaged true ] ;
val text = XmCreateLabel main "show" [ XmNlabelString "Hello World!"]
in
(
XtManageChildren [text];
XtManageChild main;
XtRealizeWidget shell
)
end;
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Standard_ML
|
Standard ML
|
fun gray_encode b =
Word.xorb (b, Word.>> (b, 0w1))
fun gray_decode n =
let
fun aux (p, n) =
if n = 0w0 then p
else aux (Word.xorb (p, n), Word.>> (n, 0w1))
in
aux (n, Word.>> (n, 0w1))
end;
val s = Word.fmt StringCvt.BIN;
fun aux i =
if i = 0w32 then
()
else
let
val g = gray_encode i
val b = gray_decode g
in
print (Word.toString i ^ " :\t" ^ s i ^ " => " ^ s g ^ " => " ^ s b ^ "\t: " ^ Word.toString b ^ "\n");
aux (i + 0w1)
end;
aux 0w0
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Swift
|
Swift
|
func grayEncode(_ i: Int) -> Int {
return (i >> 1) ^ i
}
func grayDecode(_ i: Int) -> Int {
switch i {
case 0:
return 0
case _:
return i ^ grayDecode(i >> 1)
}
}
for i in 0..<32 {
let iStr = String(i, radix: 2)
let encode = grayEncode(i)
let encodeStr = String(encode, radix: 2)
let decode = grayDecode(encode)
let decodeStr = String(decode, radix: 2)
print("\(i) (\(iStr)) => \(encode) (\(encodeStr)) => \(decode) (\(decodeStr))")
}
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#D.C3.A9j.C3.A0_Vu
|
Déjà Vu
|
swap
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Eiffel
|
Eiffel
|
class
GREATEST_ELEMENT [G -> COMPARABLE]
create
make
feature {NONE} --Implementation
is_max (element: G maximum: G): BOOLEAN
do
Result := maximum >= element
end
max (list: ARRAY [G]): G
require
not_empty: not list.is_empty
do
Result := list [list.lower]
across
list as i
loop
Result := i.item.max (Result)
end
ensure
is_part_of_array: list.has (Result)
is_maximum: list.for_all (agent is_max(?, Result))
end
feature -- Initialization
make
do
end
greatest_element (a: ARRAY [G]): G
do
Result := max (a)
end
end
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#Draco
|
Draco
|
proc nonrec gcd(word m, n) word:
word t;
while n ~= 0 do
t := m;
m := n;
n := t % n
od;
m
corp
proc nonrec show(word m, n) void:
writeln("gcd(", m, ", ", n, ") = ", gcd(m, n))
corp
proc nonrec main() void:
show(18, 12);
show(1071, 1029);
show(3528, 3780)
corp
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Erlang
|
Erlang
|
-module(hailstone).
-import(io).
-export([main/0]).
hailstone(1) -> [1];
hailstone(N) when N band 1 == 1 -> [N|hailstone(N * 3 + 1)];
hailstone(N) when N band 1 == 0 -> [N|hailstone(N div 2)].
max_length(Start, Stop) ->
F = fun (N) -> {length(hailstone(N)), N} end,
Lengths = lists:map(F, lists:seq(Start, Stop)),
lists:max(Lengths).
main() ->
io:format("hailstone(4): ~w~n", [hailstone(4)]),
Seq27 = hailstone(27),
io:format("hailstone(27) length: ~B~n", [length(Seq27)]),
io:format("hailstone(27) first 4: ~w~n",
[lists:sublist(Seq27, 4)]),
io:format("hailstone(27) last 4: ~w~n",
[lists:nthtail(length(Seq27) - 4, Seq27)]),
io:format("finding maximum hailstone(N) length for 1 <= N <= 100000..."),
{Length, N} = max_length(1, 100000),
io:format(" done.~nhailstone(~B) length: ~B~n", [N, Length]).
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#Prolog
|
Prolog
|
%% collect N elements produced by a generator in a row
take( 0, Next, Z-Z, Next).
take( N, Next, [A|B]-Z, NZ):- N>0, !, next(Next,A,Next1),
N1 is N-1,
take(N1,Next1,B-Z,NZ).
%% a generator provides specific {next} implementation
next( hamm( A2,B,C3,D,E5,F,[H|G] ), H, hamm(X,U,Y,V,Z,W,G) ):-
H is min(A2, min(C3,E5)),
( A2 =:= H -> B=[N2|U],X is N2*2 ; (X,U)=(A2,B) ),
( C3 =:= H -> D=[N3|V],Y is N3*3 ; (Y,V)=(C3,D) ),
( E5 =:= H -> F=[N5|W],Z is N5*5 ; (Z,W)=(E5,F) ).
mkHamm( hamm(1,X,1,X,1,X,X) ). % Hamming numbers generator init state
main(N) :-
mkHamm(G),take(20,G,A-[],_), write(A), nl,
take(1691-1,G,_,G2),take(2,G2,B-[],_), write(B), nl,
take( N -1,G,_,G3),take(2,G3,[C1|_]-_,_), write(C1), nl.
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Scheme
|
Scheme
|
(define (guess)
(define number (random 11))
(display "Pick a number from 1 through 10.\n> ")
(do ((guess (read) (read)))
((= guess number) (display "Well guessed!\n"))
(display "Guess again.\n")))
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
const proc: main is func
local
var integer: number is 0;
var integer: guess is 0;
begin
number := rand(1, 10);
writeln("I'm thinking of a number between 1 and 10.");
writeln("Try to guess it!");
readln(guess);
while guess <> number do
writeln("That's not my number.");
writeln("Try another guess!");
readln(guess);
end while;
writeln("You have won!");
end func;
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#zkl
|
zkl
|
fcn maxsubseq(s){
s.reduce(fcn([(sum, seq, maxsum, maxseq)], x){
sum=sum+x; seq=T(x).extend(seq);
if(sum < 0) return(0,T,maxsum,maxseq);
if (sum>maxsum) return(sum, seq, sum, seq);
return(sum, seq, maxsum, maxseq);
},
T(0,T,0,T))[3].reverse(); // -->maxseq.reverse()
}
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#ZX_Spectrum_Basic
|
ZX Spectrum Basic
|
10 DATA 12,0,1,2,-3,3,-1,0,-4,0,-1,-4,2
20 DATA 11,-1,-2,3,5,6,-2,-1,4,-4,2,-1
30 DATA 5,-1,-2,-3,-4,-5
40 FOR n=1 TO 3
50 READ l
60 DIM a(l)
70 FOR i=1 TO l
80 READ a(i)
90 PRINT a(i);
100 IF i<l THEN PRINT ", ";
110 NEXT i
120 PRINT
130 LET a=1: LET m=0: LET b=0
140 FOR i=1 TO l
150 LET s=0
160 FOR j=i TO l
170 LET s=s+a(j)
180 IF s>m THEN LET m=s: LET a=i: LET b=j
190 NEXT j
200 NEXT i
210 IF a>b THEN PRINT "[]": GO TO 280
220 PRINT "[";
230 FOR i=a TO b
240 PRINT a(i);
250 IF i<b THEN PRINT ", ";
260 NEXT i
270 PRINT "]"
280 NEXT n
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#Nanoquery
|
Nanoquery
|
import Nanoquery.Util
random = new(Random)
inclusive_range = {1, 100}
print format("Guess my target number that is between %d and %d (inclusive).\n",\
inclusive_range[0], inclusive_range[1])
target = random.getInt(inclusive_range[1]) + inclusive_range[0]
answer = 0
i = 0
while answer != target
i += 1
print format("Your guess(%d): ", i)
txt = input()
valid = true
try
answer = int(txt)
catch
println format(" I don't understand you input of '%s' ?", txt)
value = false
end
if valid
if (answer < inclusive_range[0]) or (answer > inclusive_range[1])
println " Out of range!"
else if answer = target
println " Ye-Haw!!"
else if answer < target
println " Too low."
else if answer > target
println " Too high."
end
end
end
println "\nThanks for playing."
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#NetRexx
|
NetRexx
|
/*NetRexx program to display the 1st 8 (or specified arg) happy numbers*/
limit = arg[0] /*get argument for LIMIT. */
say limit
if limit = null, limit ='' then limit=8 /*if not specified, set LIMIT to 8*/
haps = 0 /*count of happy numbers so far. */
loop n=1 while haps < limit /*search integers starting at one.*/
q=n /*Q may or may not be "happy". */
a=0
loop forever /*see if Q is a happy number. */
if q==1 then do /*if Q is unity, then it's happy*/
haps = haps + 1 /*bump the count of happy numbers.*/
say n /*display the number. */
iterate n /*and then keep looking for more. */
end
sum=0 /*initialize sum to zero. */
loop j=1 for q.length /*add the squares of the numerals.*/
sum = sum + q.substr(j,1) ** 2
end
if a[sum] then iterate n /*if already summed, Q is unhappy.*/
a[sum]=1 /*mark the sum as being found. */
q=sum /*now, lets try the Q sum. */
end
end
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#JCL
|
JCL
|
/*MESSAGE Hello world!
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Stata
|
Stata
|
window stopbox note "Goodbye, World!"
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Supernova
|
Supernova
|
I want window and the window title is "Goodbye, World".
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Tcl
|
Tcl
|
namespace eval gray {
proc encode n {
expr {$n ^ $n >> 1}
}
proc decode n {
# Compute some bit at least as large as MSB
set i [expr {2**int(ceil(log($n+1)/log(2)))}]
set b [set bprev [expr {$n & $i}]]
while {[set i [expr {$i >> 1}]]} {
set b [expr {$b | [set bprev [expr {$n & $i ^ $bprev >> 1}]]}]
}
return $b
}
}
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#TypeScript
|
TypeScript
|
// Gray code
function encode(v: number): number {
return v ^ (v >> 1);
}
function decode(v: number): number {
var result = 0;
while (v > 0) {
result ^= v;
v >>= 1;
}
return result;
}
console.log("decimal binary gray decoded");
for (var i = 0; i <= 31; i++) {
var g = encode(i);
var d = decode(g);
process.stdout.write(
" " + i.toString().padStart(2, " ") +
" " + i.toString(2).padStart(5, "0") +
" " + g.toString(2).padStart(5, "0") +
" " + d.toString(2).padStart(5, "0") +
" " + d.toString().padStart(2, " "));
console.log();
}
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#E
|
E
|
def swap(&left, &right) {
def t := left
left := right
right := t
}
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Ela
|
Ela
|
open list
findBy p (x::xs) = foldl (\x y | p x y -> x | else -> y) x xs
maximum = findBy (>)
maximum [1..10]
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#DWScript
|
DWScript
|
PrintLn(Gcd(231, 210));
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#ERRE
|
ERRE
|
PROGRAM ULAM
!$DOUBLE
PROCEDURE HAILSTONE(X,PRT%->COUNT)
COUNT=1
IF PRT% THEN PRINT(X,) END IF
REPEAT
IF X/2<>INT(X/2) THEN
X=X*3+1
ELSE
X=X/2
END IF
IF PRT% THEN PRINT(X,) END IF
COUNT=COUNT+1
UNTIL X=1
IF PRT% THEN PRINT END IF
END PROCEDURE
BEGIN
HAILSTONE(27,TRUE->COUNT)
PRINT("Sequence length for 27:";COUNT)
MAX_COUNT=2
NMAX=2
FOR I=3 TO 100000 DO
HAILSTONE(I,FALSE->COUNT)
IF COUNT>MAX_COUNT THEN NMAX=I MAX_COUNT=COUNT END IF
END FOR
PRINT("Max. number is";NMAX;" with";MAX_COUNT;"elements")
END PROGRAM
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#PureBasic
|
PureBasic
|
#X2 = 2
#X3 = 3
#X5 = 5
Macro Ham(w)
PrintN("H("+Str(w)+") = "+Str(Hamming(w)))
EndMacro
Procedure.i Hamming(l.i)
Define.i i,j,k,n,m,x=#X2,y=#X3,z=#X5
Dim h.i(l) : h(0)=1
For n=1 To l-1
m=x
If m>y : m=y : EndIf
If m>z : m=z : EndIf
h(n)=m
If m=x : i+1 : x=#X2*h(i) : EndIf
If m=y : j+1 : y=#X3*h(j) : EndIf
If m=z : k+1 : z=#X5*h(k) : EndIf
Next
ProcedureReturn h(l-1)
EndProcedure
OpenConsole("Hamming numbers")
For h.i=1 To 20
Ham(h)
Next
Ham(1691)
Input()
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Self
|
Self
|
(|
parent* = traits clonable.
copy = (resend.copy secretNumber: random integerBetween: 1 And: 10).
secretNumber.
ask = ((userQuery askString: 'Guess the Number: ') asInteger).
reportSuccess = (userQuery report: 'You got it!').
reportFailure = (userQuery report: 'Nope. Guess again.').
sayIntroduction = (userQuery report: 'Try to guess my secret number between 1 and 10.').
hasGuessed = ( [ask = secretNumber] onReturn: [|:r| r ifTrue: [reportSuccess] False: [reportFailure]] ).
run = (sayIntroduction. [hasGuessed] whileFalse)
|) copy run
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#Nemerle
|
Nemerle
|
using System;
using System.Console;
module GuessHints
{
Main() : void
{
def rand = Random();
def secret = rand.Next(1, 101);
mutable guess = 0;
def GetGuess() : int {Int32.Parse(ReadLine())}
WriteLine("Guess a number between 1 and 100:");
do
{
guess = GetGuess();
match(guess.CompareTo(secret))
{
|(-1) => WriteLine("Too low! Guess again:")
|1 => WriteLine("Too high! Guess again:")
|0 => WriteLine("Well guessed!")
}
} while (guess != secret)
}
}
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#Nim
|
Nim
|
import intsets
proc happy(n: int): bool =
var
n = n
past = initIntSet()
while n != 1:
let s = $n
n = 0
for c in s:
let i = ord(c) - ord('0')
n += i * i
if n in past:
return false
past.incl(n)
return true
for x in 0..31:
if happy(x):
echo x
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Jinja
|
Jinja
|
from jinja2 import Template
print(Template("Hello World!").render())
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Swift
|
Swift
|
import Cocoa
let alert = NSAlert()
alert.messageText = "Goodbye, World!"
alert.runModal()
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Tcl
|
Tcl
|
pack [label .l -text "Goodbye, World"]
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Ursala
|
Ursala
|
#import std
#import nat
xor = ~&Y&& not ~&B # either and not both
btog = xor*+ zipp0@iitBX # map xor over the argument zipped with its shift
gtob = ~&y+ =><0> ^C/xor@lrhPX ~&r # fold xor over the next input with previous output
#show+
test = mat` * 2-$'01'***K7xSS pad0*K7 <.~&,btog,gtob+ btog>* iota32
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#VBScript
|
VBScript
|
Function Encoder(ByVal n)
Encoder = n Xor (n \ 2)
End Function
Function Decoder(ByVal n)
Dim g : g = 0
Do While n > 0
g = g Xor n
n = n \ 2
Loop
Decoder = g
End Function
' Decimal to Binary
Function Dec2bin(ByVal n, ByVal length)
Dim i, strbin : strbin = ""
For i = 1 to 5
strbin = (n Mod 2) & strbin
n = n \ 2
Next
Dec2Bin = strbin
End Function
WScript.StdOut.WriteLine("Binary -> Gray Code -> Binary")
For i = 0 to 31
encoded = Encoder(i)
decoded = Decoder(encoded)
WScript.StdOut.WriteLine(Dec2Bin(i, 5) & " -> " & Dec2Bin(encoded, 5) & " -> " & Dec2Bin(decoded, 5))
Next
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#EchoLisp
|
EchoLisp
|
;; 1)
;; a macro will do it, as shown in Racket (same syntax)
(define-syntax-rule (swap a b)
(let ([tmp a])
(set! a b)
(set! b tmp)))
(define A 666)
(define B "simon")
(swap A B)
A → "simon"
B → 666
;; 2)
;; The list-swap! function allows to swap two items inside a list, regardless of their types
;; This physically alters the list
(define L ' ( 1 2 3 4 🎩 ))
(list-swap! L 1 ' 🎩 )
→ (🎩 2 3 4 1)
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Elena
|
Elena
|
import extensions;
extension op
{
get Maximal()
{
auto en := cast Enumerator(self.enumerator());
object maximal := nil;
while (en.next())
{
var item := en.get();
if (nil == maximal)
{
maximal := item
}
else if (maximal < item)
{
maximal := item
}
};
^ maximal
}
}
public program()
{
console.printLine(new int[]{1,2,3,4,20,10,9,8}.Maximal)
}
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#Dyalect
|
Dyalect
|
func gcd(a, b) {
func bgcd(a, b, res) {
if a == b {
return res * a
} else if a % 2 == 0 && b % 2 == 0 {
return bgcd(a/2, b/2, 2*res)
} else if a % 2 == 0 {
return bgcd(a/2, b, res)
} else if b % 2 == 0 {
return bgcd(a, b/2, res)
} else if a > b {
return bgcd(a-b, b, res)
} else {
return bgcd(a, b-a, res)
}
}
return bgcd(a, b, 1)
}
var testdata = [
(a: 33, b: 77),
(a: 49865, b: 69811)
]
for v in testdata {
print("gcd(\(v.a), \(v.b)) = \(gcd(v.a, v.b))")
}
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Euler_Math_Toolbox
|
Euler Math Toolbox
|
>function hailstone (n) ...
$ v=[n];
$ repeat
$ if mod(n,2) then n=3*n+1;
$ else n=n/2;
$ endif;
$ v=v|n;
$ until n==1;
$ end;
$ return v;
$ endfunction
>hailstone(27), length(%)
[ 27 82 41 124 62 31 94 47 142 71 214 107 322 161 484 242
121 364 182 91 274 137 412 206 103 310 155 466 233 700
350 175 526 263 790 395 1186 593 1780 890 445 1336 668
334 167 502 251 754 377 1132 566 283 850 425 1276 638 319
958 479 1438 719 2158 1079 3238 1619 4858 2429 7288 3644
1822 911 2734 1367 4102 2051 6154 3077 9232 4616 2308 1154
577 1732 866 433 1300 650 325 976 488 244 122 61 184 92
46 23 70 35 106 53 160 80 40 20 10 5 16 8 4 2 1 ]
112
>function hailstonelength (n) ...
$ v=zeros(1,n);
$ v[1]=4; v[2]=2;
$ loop 3 to n;
$ count=1;
$ n=#;
$ repeat
$ if mod(n,2) then n=3*n+1;
$ else n=n/2;
$ endif;
$ if n<=cols(v) and v[n] then
$ v[#]=v[n]+count;
$ break;
$ endif;
$ count=count+1;
$ end;
$ end;
$ return v;
$ endfunction
>h=hailstonelength(100000);
>ex=extrema(h); ex[3], ex[4]
351
77031
|
http://rosettacode.org/wiki/Hamming_numbers
|
Hamming numbers
|
Hamming numbers are numbers of the form
H = 2i × 3j × 5k
where
i, j, k ≥ 0
Hamming numbers are also known as ugly numbers and also 5-smooth numbers (numbers whose prime divisors are less or equal to 5).
Task
Generate the sequence of Hamming numbers, in increasing order. In particular:
Show the first twenty Hamming numbers.
Show the 1691st Hamming number (the last one below 231).
Show the one millionth Hamming number (if the language – or a convenient library – supports arbitrary-precision integers).
Related tasks
Humble numbers
N-smooth numbers
References
Wikipedia entry: Hamming numbers (this link is re-directed to Regular number).
Wikipedia entry: Smooth number
OEIS entry: A051037 5-smooth or Hamming numbers
Hamming problem from Dr. Dobb's CodeTalk (dead link as of Sep 2011; parts of the thread here and here).
|
#Python
|
Python
|
from itertools import islice
def hamming2():
'''\
This version is based on a snippet from:
https://web.archive.org/web/20081219014725/http://dobbscodetalk.com:80
/index.php?option=com_content&task=view&id=913&Itemid=85
http://www.drdobbs.com/architecture-and-design/hamming-problem/228700538
Hamming problem
Written by Will Ness
December 07, 2008
When expressed in some imaginary pseudo-C with automatic
unlimited storage allocation and BIGNUM arithmetics, it can be
expressed as:
hamming = h where
array h;
n=0; h[0]=1; i=0; j=0; k=0;
x2=2*h[ i ]; x3=3*h[j]; x5=5*h[k];
repeat:
h[++n] = min(x2,x3,x5);
if (x2==h[n]) { x2=2*h[++i]; }
if (x3==h[n]) { x3=3*h[++j]; }
if (x5==h[n]) { x5=5*h[++k]; }
'''
h = 1
_h=[h] # memoized
multipliers = (2, 3, 5)
multindeces = [0 for i in multipliers] # index into _h for multipliers
multvalues = [x * _h[i] for x,i in zip(multipliers, multindeces)]
yield h
while True:
h = min(multvalues)
_h.append(h)
for (n,(v,x,i)) in enumerate(zip(multvalues, multipliers, multindeces)):
if v == h:
i += 1
multindeces[n] = i
multvalues[n] = x * _h[i]
# cap the memoization
mini = min(multindeces)
if mini >= 1000:
del _h[:mini]
multindeces = [i - mini for i in multindeces]
#
yield h
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Sidef
|
Sidef
|
var n = irand(1, 10)
var msg = 'Guess the number: '
while (n != read(msg, Number)) {
msg = 'Wrong! Guess again: '
}
say 'Well guessed!'
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Small_Basic
|
Small Basic
|
number=Math.GetRandomNumber(10)
TextWindow.WriteLine("I just thought of a number between 1 and 10. What is it?")
While guess<>number
guess=TextWindow.ReadNumber()
TextWindow.WriteLine("Guess again! ")
EndWhile
TextWindow.WriteLine("You win!")
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback
|
Guess the number/With feedback
|
Task
Write a game (computer program) that follows the following rules:
The computer chooses a number between given set limits.
The player is asked for repeated guesses until the the target number is guessed correctly
At each guess, the computer responds with whether the guess is:
higher than the target,
equal to the target,
less than the target, or
the input was inappropriate.
Related task
Guess the number/With Feedback (Player)
|
#NetRexx
|
NetRexx
|
/* NetRexx */
options replace format comments java crossref symbols nobinary
parse arg lo hi .
if lo = '' | lo = '.' then lo = 1
if hi = '' | hi = '.' then hi = 100
if lo > hi then parse (hi lo) lo hi -- make sure lo is < hi
rg = Random()
tries = 0
guessThis = rg.nextInt(hi - lo) + lo
say
say 'Rules: Guess a number between' lo 'and' hi
say ' Use QUIT or . to stop the game'
say ' Use TELL to get the game to tell you the answer.'
say
say 'Starting...'
say
loop label g_ forever
say 'Try guessing a number between' lo 'and' hi
parse ask guess .
select
when guess.upper = 'QUIT' | guess = '.' then do
say 'You asked to leave the game. Goodbye...'
leave g_
end
when guess.upper = 'TELL' | guess = '.' then do
say 'The number you were looking for is' guessThis
end
when \guess.datatype('w') then do
say guess 'is not a whole number. Try again.'
end
when guess = guessThis then do
tries = tries + 1
say 'Well guessed!' guess 'is the correct number.'
say 'It took you' tries 'tries.'
leave g_
end
when guess < lo then do
tries = tries + 1
say guess 'is below the lower limit of' lo
end
when guess > hi then do
tries = tries + 1
say guess 'is above the upper limit of' hi
end
when guess < guessThis then do
tries = tries + 1
say guess 'is too low. Try again.'
end
when guess > guessThis then do
tries = tries + 1
say guess 'is too high. Try again.'
end
otherwise do
say guess 'is an unexpected value.'
end
end
end g_
return
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#Objeck
|
Objeck
|
use IO;
use Structure;
bundle Default {
class HappyNumbers {
function : native : IsHappy(n : Int) ~ Bool {
cache := IntVector->New();
sum := 0;
while(n <> 1) {
if(cache->Has(n)) {
return false;
};
cache->AddBack(n);
while(n <> 0) {
digit := n % 10;
sum += (digit * digit);
n /= 10;
};
n := sum;
sum := 0;
};
return true;
}
function : Main(args : String[]) ~ Nil {
num := 1;
happynums := IntVector->New();
while(happynums->Size() < 8) {
if(IsHappy(num)) {
happynums->AddBack(num);
};
num += 1;
};
Console->Print("First 8 happy numbers: ");
each(i : happynums) {
Console->Print(happynums->Get(i))->Print(",");
};
Console->PrintLine("");
}
}
}
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#Joy
|
Joy
|
"Hello world!" putchars.
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#TI-83_BASIC
|
TI-83 BASIC
|
PROGRAM:GUIHELLO
:Text(0,0,"GOODBYE, WORLD!")
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#TI-89_BASIC
|
TI-89 BASIC
|
Dialog
Text "Goodbye, World!"
EndDlog
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Verilog
|
Verilog
|
`timescale 1ns/10ps
`default_nettype wire
module graytestbench;
localparam aw = 8;
function [aw:0] binn_to_gray;
input [aw:0] binn;
begin :b2g
binn_to_gray = binn ^ (binn >> 1);
end
endfunction
function [aw:0] gray_to_binn;
input [aw:0] gray;
begin :g2b
reg [aw:0] binn;
integer i;
for(i=0; i <= aw; i = i+1) begin
binn[i] = ^(gray >> i);
end
gray_to_binn = binn;
end
endfunction
initial begin :test_graycode
integer ii;
reg[aw:0] gray;
reg[aw:0] binn;
for(ii=0; ii < 10; ii=ii+1) begin
gray = binn_to_gray(ii[aw:0]);
binn = gray_to_binn(gray);
$display("test_graycode: i:%x gray:%x:%b binn:%x", ii[aw:0], gray, gray, binn);
end
$stop;
end
endmodule
`default_nettype none
|
http://rosettacode.org/wiki/Generic_swap
|
Generic swap
|
Task
Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
If your solution language is statically typed please describe the way your language provides genericity.
If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
That is to say, solutions do not have to be capable of exchanging, say, a string and integer value, if the underlying storage locations are not attributed with types that permit such an exchange.
Generic swap is a task which brings together a few separate issues in programming language semantics.
Dynamically typed languages deal with values in a generic way quite readily, but do not necessarily make it easy to write a function to destructively swap two variables, because this requires indirection upon storage places or upon the syntax designating storage places.
Functional languages, whether static or dynamic, do not necessarily allow a destructive operation such as swapping two variables regardless of their generic capabilities.
Some static languages have difficulties with generic programming due to a lack of support for (Parametric Polymorphism).
Do your best!
|
#Elena
|
Elena
|
import extensions;
swap(ref object v1, ref object v2)
{
var tmp := v1;
v1 := v2;
v2 := tmp
}
public program()
{
var n := 2;
var s := "abc";
console.printLine(n," ",s);
swap(ref n, ref s);
console.printLine(n," ",s)
}
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Elixir
|
Elixir
|
iex(1)> Enum.max([3,1,4,1,5,9,2,6,5,3])
9
|
http://rosettacode.org/wiki/Greatest_element_of_a_list
|
Greatest element of a list
|
Task
Create a function that returns the maximum value in a provided set of values,
where the number of values may not be known until run-time.
|
#Emacs_Lisp
|
Emacs Lisp
|
(defun find-maximum (items)
(let (max)
(dolist (item items)
(when (or (not max) (> item max))
(setq max item)))
max))
(find-maximum '(2 7 5)) ;=> 7
|
http://rosettacode.org/wiki/Greatest_common_divisor
|
Greatest common divisor
|
Greatest common divisor
You are encouraged to solve this task according to the task description, using any language you may know.
Task
Find the greatest common divisor (GCD) of two integers.
Greatest common divisor is also known as greatest common factor (gcf) and greatest common measure.
Related task
least common multiple.
See also
MathWorld entry: greatest common divisor.
Wikipedia entry: greatest common divisor.
|
#E
|
E
|
def gcd(var u :int, var v :int) {
while (v != 0) {
def r := u %% v
u := v
v := r
}
return u.abs()
}
|
http://rosettacode.org/wiki/Hailstone_sequence
|
Hailstone sequence
|
The Hailstone sequence of numbers can be generated from a starting positive integer, n by:
If n is 1 then the sequence ends.
If n is even then the next n of the sequence = n/2
If n is odd then the next n of the sequence = (3 * n) + 1
The (unproven) Collatz conjecture is that the hailstone sequence for any starting number always terminates.
This sequence was named by Lothar Collatz in 1937 (or possibly in 1939), and is also known as (the):
hailstone sequence, hailstone numbers
3x + 2 mapping, 3n + 1 problem
Collatz sequence
Hasse's algorithm
Kakutani's problem
Syracuse algorithm, Syracuse problem
Thwaites conjecture
Ulam's problem
The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud).
Task
Create a routine to generate the hailstone sequence for a number.
Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with 27, 82, 41, 124 and ending with 8, 4, 2, 1
Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length.
(But don't show the actual sequence!)
See also
xkcd (humourous).
The Notorious Collatz conjecture Terence Tao, UCLA (Presentation, pdf).
The Simplest Math Problem No One Can Solve Veritasium (video, sponsored).
|
#Euphoria
|
Euphoria
|
function hailstone(atom n)
sequence s
s = {n}
while n != 1 do
if remainder(n,2)=0 then
n /= 2
else
n = 3*n + 1
end if
s &= n
end while
return s
end function
function hailstone_count(atom n)
integer count
count = 1
while n != 1 do
if remainder(n,2)=0 then
n /= 2
else
n = 3*n + 1
end if
count += 1
end while
return count
end function
sequence s
s = hailstone(27)
puts(1,"hailstone(27) =\n")
? s
printf(1,"len = %d\n\n",length(s))
integer max,imax,count
max = 0
for i = 2 to 1e5-1 do
count = hailstone_count(i)
if count > max then
max = count
imax = i
end if
end for
printf(1,"The longest hailstone sequence under 100,000 is %d with %d elements.\n",
{imax,max})
|
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