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http://rosettacode.org/wiki/Haversine_formula
|
Haversine formula
|
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes.
It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles".
Task
Implement a great-circle distance function, or use a library function,
to show the great-circle distance between:
Nashville International Airport (BNA) in Nashville, TN, USA, which is:
N 36°7.2', W 86°40.2' (36.12, -86.67) -and-
Los Angeles International Airport (LAX) in Los Angeles, CA, USA, which is:
N 33°56.4', W 118°24.0' (33.94, -118.40)
User Kaimbridge clarified on the Talk page:
-- 6371.0 km is the authalic radius based on/extracted from surface area;
-- 6372.8 km is an approximation of the radius of the average circumference
(i.e., the average great-elliptic or great-circle radius), where the
boundaries are the meridian (6367.45 km) and the equator (6378.14 km).
Using either of these values results, of course, in differing distances:
6371.0 km -> 2886.44444283798329974715782394574671655 km;
6372.8 km -> 2887.25995060711033944886005029688505340 km;
(results extended for accuracy check: Given that the radii are only
approximations anyways, .01' ≈ 1.0621333 km and .001" ≈ .00177 km,
practical precision required is certainly no greater than about
.0000001——i.e., .1 mm!)
As distances are segments of great circles/circumferences, it is
recommended that the latter value (r = 6372.8 km) be used (which
most of the given solutions have already adopted, anyways).
Most of the examples below adopted Kaimbridge's recommended value of
6372.8 km for the earth radius. However, the derivation of this
ellipsoidal quadratic mean radius
is wrong (the averaging over azimuth is biased). When applying these
examples in real applications, it is better to use the
mean earth radius,
6371 km. This value is recommended by the International Union of
Geodesy and Geophysics and it minimizes the RMS relative error between the
great circle and geodesic distance.
|
#Oforth
|
Oforth
|
import: math
: haversine(lat1, lon1, lat2, lon2)
| lat lon |
lat2 lat1 - asRadian ->lat
lon2 lon1 - asRadian ->lon
lon 2 / sin sq lat1 asRadian cos * lat2 asRadian cos *
lat 2 / sin sq + sqrt asin 2 * 6372.8 * ;
haversine(36.12, -86.67, 33.94, -118.40) println
|
http://rosettacode.org/wiki/Haversine_formula
|
Haversine formula
|
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes.
It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles".
Task
Implement a great-circle distance function, or use a library function,
to show the great-circle distance between:
Nashville International Airport (BNA) in Nashville, TN, USA, which is:
N 36°7.2', W 86°40.2' (36.12, -86.67) -and-
Los Angeles International Airport (LAX) in Los Angeles, CA, USA, which is:
N 33°56.4', W 118°24.0' (33.94, -118.40)
User Kaimbridge clarified on the Talk page:
-- 6371.0 km is the authalic radius based on/extracted from surface area;
-- 6372.8 km is an approximation of the radius of the average circumference
(i.e., the average great-elliptic or great-circle radius), where the
boundaries are the meridian (6367.45 km) and the equator (6378.14 km).
Using either of these values results, of course, in differing distances:
6371.0 km -> 2886.44444283798329974715782394574671655 km;
6372.8 km -> 2887.25995060711033944886005029688505340 km;
(results extended for accuracy check: Given that the radii are only
approximations anyways, .01' ≈ 1.0621333 km and .001" ≈ .00177 km,
practical precision required is certainly no greater than about
.0000001——i.e., .1 mm!)
As distances are segments of great circles/circumferences, it is
recommended that the latter value (r = 6372.8 km) be used (which
most of the given solutions have already adopted, anyways).
Most of the examples below adopted Kaimbridge's recommended value of
6372.8 km for the earth radius. However, the derivation of this
ellipsoidal quadratic mean radius
is wrong (the averaging over azimuth is biased). When applying these
examples in real applications, it is better to use the
mean earth radius,
6371 km. This value is recommended by the International Union of
Geodesy and Geophysics and it minimizes the RMS relative error between the
great circle and geodesic distance.
|
#ooRexx
|
ooRexx
|
/*REXX pgm calculates distance between Nashville & Los Angles airports. */
say " Nashville: north 36º 7.2', west 86º 40.2' = 36.12º, -86.67º"
say "Los Angles: north 33º 56.4', west 118º 24.0' = 33.94º, -118.40º"
say
dist=surfaceDistance(36.12, -86.67, 33.94, -118.4)
kdist=format(dist/1 ,,2) /*show 2 digs past decimal point.*/
mdist=format(dist/1.609344,,2) /* " " " " " " */
ndist=format(mdist*5280/6076.1,,2) /* " " " " " " */
say ' distance between= ' kdist " kilometers,"
say ' or ' mdist " statute miles,"
say ' or ' ndist " nautical or air miles."
exit /*stick a fork in it, we're done.*/
/*----------------------------------SURFACEDISTANCE subroutine----------*/
surfaceDistance: arg th1,ph1,th2,ph2 /*use haversine formula for dist.*/
radius = 6372.8 /*earth's mean radius in km */
ph1 = ph1-ph2
x = cos(ph1) * cos(th1) - cos(th2)
y = sin(ph1) * cos(th1)
z = sin(th1) - sin(th2)
return radius * 2 * aSin(sqrt(x**2+y**2+z**2)/2 )
cos: Return RxCalcCos(arg(1))
sin: Return RxCalcSin(arg(1))
asin: Return RxCalcArcSin(arg(1),,'R')
sqrt: Return RxCalcSqrt(arg(1))
::requires rxMath library
|
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
|
#GLBasic
|
GLBasic
|
STDOUT "Hello world!"
|
http://rosettacode.org/wiki/Harshad_or_Niven_series
|
Harshad or Niven series
|
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is to create a function/method/procedure to generate successive members of the Harshad sequence.
Use it to:
list the first 20 members of the sequence, and
list the first Harshad number greater than 1000.
Show your output here.
Related task
Increasing gaps between consecutive Niven numbers
See also
OEIS: A005349
|
#PicoLisp
|
PicoLisp
|
#if niven number, return it.
(de niven (N)
(if (=0 (% N (apply + (getN N)))) N) )
#function which creates a list of numbers from input
(de getN (N)
(mapcar format (chop N)) )
#This function generates niven number list
(de nivGen (R N)
(extract niven (range R N)) )
#print 1st 20 niven numbers and 1st niven number greater than 1000
(printsp ~(list ~(head 20
(nivGen 1 1000) ) (max ~(nivGen 1001 1010)) ) )
|
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
|
#Just_Basic
|
Just Basic
|
print "Goodbye, World!"
'Prints in the upper left corner of the default text window: mainwin, a window with scroll bars.
|
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
|
#KonsolScript
|
KonsolScript
|
function main() {
Konsol:Message("Goodbye, World!", "")
}
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Ring
|
Ring
|
Load "guilib.ring"
MyApp = New qApp {
num = 0
win1 = new qWidget() {
setwindowtitle("Hello World")
setGeometry(100,100,370,250)
btn1 = new qpushbutton(win1) {
setGeometry(200,200,100,30)
settext("Random")
setclickevent("Rand()")}
btn2 = new qpushbutton(win1) {
setGeometry(50,200,100,30)
settext("Increment")
setclickevent("Increment()")}
lineedit1 = new qlineedit(win1) {
setGeometry(10,100,350,30)}
show()}
exec()}
func Rand
num = string(random(10000))
lineedit1.settext(num)
func Increment
lineedit1{ num = text()}
num = string(number(num)+1)
lineedit1.settext(num)
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Ruby
|
Ruby
|
Shoes.app(title: "GUI component interaction") do
stack do
textbox = edit_line
textbox.change do
textbox.text = textbox.text.gsub(/[^\d]/, '') and alert "Input must be a number!" if textbox.text !~ /^\d*$/
end
flow do
button "Increment" do
textbox.text = textbox.text.to_i + 1
end
button "Random" do
textbox.text = rand 5000 if confirm "Do you want a random number?"
end
end
end
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.
|
#Batch_File
|
Batch File
|
:: Gray Code Task from Rosetta Code
:: Batch File Implementation
@echo off
rem -------------- define batch file macros with parameters appended
rem more info: https://www.dostips.com/forum/viewtopic.php?f=3&t=2518
setlocal disabledelayedexpansion % == required for macro ==%
(set \n=^^^
%== this creates escaped line feed for macro ==%
)
rem convert to binary (unsigned)
rem argument: natnum bitlength outputvar
rem note: if natnum is negative, then !outputvar! is empty
set tobinary=for %%# in (1 2) do if %%#==2 ( %\n%
for /f "tokens=1,2,3" %%a in ("!args!") do ( %\n%
set "natnum=%%a"^&set "bitlength=%%b"^&set "outputvar=%%c") %\n%
set "!outputvar!=" %\n%
if !natnum! geq 0 ( %\n%
set "currnum=!natnum!" %\n%
for /l %%m in (1,1,!bitlength!) do ( %\n%
set /a "bit=!currnum!%%2" %\n%
for %%v in (!outputvar!) do set "!outputvar!=!bit!!%%v!" %\n%
set /a "currnum/=2" %\n%
) %\n%
) %\n%
) else set args=
goto :main-thing %== jump to the main thing ==%
rem -------------- usual "call" sections
rem the sad disadvantage of using these is that they are slow (TnT)
rem gray code encoder
rem argument: natnum outputvar
:encoder
set /a "%~2=%~1^(%~1>>1)"
goto :eof
rem gray code decoder
rem argument: natnum outputvar
:decoder
set "inp=%~1" & set "%~2=0"
:while-loop-1
if %inp% gtr 0 (
set /a "%~2^=%inp%, inp>>=1"
goto while-loop-1
)
goto :eof
rem -------------- main thing
:main-thing
setlocal enabledelayedexpansion
echo(# -^> bin -^> enc -^> dec
for /l %%n in (0,1,31) do (
%tobinary% %%n 5 bin
call :encoder "%%n" "enc"
%tobinary% !enc! 5 gray
call :decoder "!enc!" "dec"
%tobinary% !dec! 5 rebin
echo(%%n -^> !bin! -^> !gray! -^> !rebin!
)
exit /b 0
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#Arturo
|
Arturo
|
print split.lines execute "ls"
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#AWK
|
AWK
|
BEGIN {
# For Windows
out = system2var("dir")
print out
# Non-Windows
out = getline2var("ls -l")
print out
}
# For a Windows environment using system() method
function system2var(command ,tempfile, cmd, out, rec, data, i) {
tempfile = "C:\\TEMP\\TMP.TMP"
cmd = command " > " tempfile
system(cmd)
close(cmd)
while (getline rec < tempfile > 0) {
if ( ++i == 1 )
data = rec
else
data = data "\n" rec
}
return(data)
}
# If command returns an ERRNO function returns null string
function getline2var(command ,fish, scale, ship) {
command = command " 2>/dev/null"
while ( (command | getline fish) > 0 ) {
if ( ++scale == 1 )
ship = fish
else
ship = ship "\n" fish
}
close(command)
return ship
}
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#BaCon
|
BaCon
|
' Get system command
result$ = EXEC$("fortune")
PRINT CHOP$(result$)
PRINT "First word: " & TOKEN$(result$, 1)
|
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!
|
#11l
|
11l
|
F swap(&a, &b)
(a, b) = (b, a)
|
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.
|
#Amazing_Hopper
|
Amazing Hopper
|
#include <hopper.h>
main:
lst=0
max=0
file="datos.txt"
{","} toksep
{file} statsfile
{file} load
mov (lst)
{0} reshape (lst)
{lst} array (SORT)
[end] get (lst)
mov (max)
{"Maximo = "}
{max}
{"\n"} print
exit(0)
|
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.
|
#AntLang
|
AntLang
|
max|range[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.
|
#ACL2
|
ACL2
|
(include-book "arithmetic-3/floor-mod/floor-mod" :dir :system)
(defun gcd$ (x y)
(declare (xargs :guard (and (natp x) (natp y))))
(cond ((or (not (natp x)) (< y 0))
nil)
((zp y) x)
(t (gcd$ y (mod x y)))))
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#C
|
C
|
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <err.h>
#include <string.h>
char * find_match(const char *buf, const char * buf_end, const char *pat, size_t len)
{
ptrdiff_t i;
char *start = buf;
while (start + len < buf_end) {
for (i = 0; i < len; i++)
if (start[i] != pat[i]) break;
if (i == len) return (char *)start;
start++;
}
return 0;
}
int replace(const char *from, const char *to, const char *fname)
{
#define bail(msg) { warn(msg" '%s'", fname); goto done; }
struct stat st;
int ret = 0;
char *buf = 0, *start, *end;
size_t len = strlen(from), nlen = strlen(to);
int fd = open(fname, O_RDWR);
if (fd == -1) bail("Can't open");
if (fstat(fd, &st) == -1) bail("Can't stat");
if (!(buf = malloc(st.st_size))) bail("Can't alloc");
if (read(fd, buf, st.st_size) != st.st_size) bail("Bad read");
start = buf;
end = find_match(start, buf + st.st_size, from, len);
if (!end) goto done; /* no match found, don't change file */
ftruncate(fd, 0);
lseek(fd, 0, 0);
do {
write(fd, start, end - start); /* write content before match */
write(fd, to, nlen); /* write replacement of match */
start = end + len; /* skip to end of match */
/* find match again */
end = find_match(start, buf + st.st_size, from, len);
} while (end);
/* write leftover after last match */
if (start < buf + st.st_size)
write(fd, start, buf + st.st_size - start);
done:
if (fd != -1) close(fd);
if (buf) free(buf);
return ret;
}
int main()
{
const char *from = "Goodbye, London!";
const char *to = "Hello, New York!";
const char * files[] = { "test1.txt", "test2.txt", "test3.txt" };
int i;
for (i = 0; i < sizeof(files)/sizeof(char*); i++)
replace(from, to, files[i]);
return 0;
}
|
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).
|
#ALGOL_68
|
ALGOL 68
|
MODE LINT = # LONG ... # INT;
PROC hailstone = (INT in n, REF[]LINT array)INT:
(
INT hs := 1;
INT index := 0;
LINT n := in n;
WHILE n /= 1 DO
hs +:= 1;
IF array ISNT REF[]LINT(NIL) THEN array[index +:= 1] := n FI;
n := IF ODD n THEN 3*n+1 ELSE n OVER 2 FI
OD;
IF array ISNT REF[]LINT(NIL) THEN array[index +:= 1] := n FI;
hs
);
main:
(
INT j, hmax := 0;
INT jatmax, n;
INT border = 4;
FOR j TO 100000-1 DO
n := hailstone(j, NIL);
IF hmax < n THEN
hmax := n;
jatmax := j
FI
OD;
[2]INT test := (27, jatmax);
FOR key TO UPB test DO
INT val = test[key];
n := hailstone(val, NIL);
[n]LINT array;
n := hailstone(val, array);
printf(($"[ "n(border)(g(0)", ")" ..."n(border)(", "g(0))"] len="g(0)l$,
array[:border], array[n-border+1:], n))
#;free(array) #
OD;
printf(($"Max "g(0)" at j="g(0)l$, hmax, jatmax))
# ELLA Algol68RS:
print(("Max",hmax," at j=",jatmax, new line))
#
)
|
http://rosettacode.org/wiki/Grayscale_image
|
Grayscale image
|
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color use the formula recommended by CIE:
L = 0.2126 × R + 0.7152 × G + 0.0722 × B
When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
|
#Go
|
Go
|
package raster
import (
"math"
"math/rand"
)
// Grmap parallels Bitmap, but with an element type of uint16
// in place of Pixel.
type Grmap struct {
Comments []string
rows, cols int
px []uint16
pxRow [][]uint16
}
// NewGrmap constructor.
func NewGrmap(x, y int) (b *Grmap) {
g := &Grmap{
Comments: []string{creator}, // creator a const in bitmap source file
rows: y,
cols: x,
px: make([]uint16, x*y),
pxRow: make([][]uint16, y),
}
x0, x1 := 0, x
for i := range g.pxRow {
g.pxRow[i] = g.px[x0:x1]
x0, x1 = x1, x1+x
}
return g
}
func (b *Grmap) Extent() (cols, rows int) {
return b.cols, b.rows
}
func (g *Grmap) Fill(c uint16) {
for i := range g.px {
g.px[i] = c
}
}
func (g *Grmap) SetPx(x, y int, c uint16) bool {
defer func() { recover() }()
g.pxRow[y][x] = c
return true
}
func (g *Grmap) GetPx(x, y int) (uint16, bool) {
defer func() { recover() }()
return g.pxRow[y][x], true
}
// Grmap method of Bitmap, converts (color) Bitmap to (grayscale) Grmap
func (b *Bitmap) Grmap() *Grmap {
g := NewGrmap(b.cols, b.rows)
g.Comments = append([]string{}, b.Comments...)
for i, p := range b.px {
g.px[i] = uint16((int64(p.R)*2126 + int64(p.G)*7152 + int64(p.B)*722) *
math.MaxUint16 / (math.MaxUint8 * 10000))
}
return g
}
// Bitmap method Grmap, converts Grmap to Bitmap. All pixels in the resulting
// color Bitmap will be (very nearly) shades of gray.
func (g *Grmap) Bitmap() *Bitmap {
b := NewBitmap(g.cols, g.rows)
b.Comments = append([]string{}, g.Comments...)
for i, p := range g.px {
roundedSum := int(p) * 3 * math.MaxUint8 / math.MaxUint16
rounded := uint8(roundedSum / 3)
remainder := roundedSum % 3
b.px[i].R = rounded
b.px[i].G = rounded
b.px[i].B = rounded
if remainder > 0 {
odd := rand.Intn(3)
switch odd + (remainder * 3) {
case 3:
b.px[i].R++
case 4:
b.px[i].G++
case 5:
b.px[i].B++
case 6:
b.px[i].G++
b.px[i].B++
case 7:
b.px[i].R++
b.px[i].B++
case 8:
b.px[i].R++
b.px[i].G++
}
}
}
return b
}
|
http://rosettacode.org/wiki/Go_Fish
|
Go Fish
|
Write a program to let the user play Go Fish against a computer opponent. Use the following rules:
Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more.
If the opponent has any cards of the named rank, they must hand over all such cards, and the requester can ask again.
If the opponent has no cards of the named rank, the requester draws a card and ends their turn.
A book is a collection of every card of a given rank. Whenever a player completes a book, they may remove it from their hand.
If at any time a player's hand is empty, they may immediately draw a new card, so long as any new cards remain in the deck.
The game ends when every book is complete. The player with the most books wins.
The game's AI need not be terribly smart, but it should use at least some strategy. That is, it shouldn't choose legal moves entirely at random.
You may want to use code from Playing Cards.
Related tasks:
Playing cards
Card shuffles
Deal cards_for_FreeCell
War Card_Game
Poker hand_analyser
|
#Java
|
Java
|
#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Go_Fish
use warnings;
use List::Util qw( first shuffle );
my $pat = qr/[atjqk2-9]/; # ranks
my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) }
qw( a t j q k ), 2 .. 9;
my $mebooks = my $youbooks = 0;
my $me = substr $deck, 0, 2 * 9, '';
my $mepicks = join '', $me =~ /$pat/g;
arrange($me);
$mebooks++ while $me =~ s/($pat).\1.\1.\1.//;
my $you = substr $deck, 0, 2 * 9, '';
my $youpicks = join '', $you =~ /$pat/g;
arrange($you);
$youbooks++ while $you =~ s/($pat).\1.\1.\1.//;
while( $mebooks + $youbooks < 13 )
{
play( \$you, \$youbooks, \$youpicks, \$me, \$mebooks, 1 );
$mebooks + $youbooks == 13 and last;
play( \$me, \$mebooks, \$mepicks, \$you, \$youbooks, 0 );
}
print "me $mebooks you $youbooks\n";
sub arrange { $_[0] = join '', sort $_[0] =~ /../g }
sub human
{
my $have = shift =~ s/($pat).\K(?!\1)/ /gr;
local $| = 1;
my $pick;
do
{
print "You have $have, enter request: ";
($pick) = lc(<STDIN>) =~ /$pat/g;
} until $pick and $have =~ /$pick/;
return $pick;
}
sub play
{
my ($me, $mb, $lastpicks, $you, $yb, $human) = @_;
my $more = 1;
while( arrange( $$me ), $more and $$mb + $$yb < 13 )
{
# use Data::Dump 'dd'; dd \@_, "deck $deck";
if( $$me =~ s/($pat).\1.\1.\1.// )
{
print "book of $&\n";
$$mb++;
}
elsif( $$me )
{
my $pick = $human ? do { human($$me) } : do
{
my %picks;
$picks{$_}++ for my @picks = $$me =~ /$pat/g;
my $pick = first { $picks{$_} } split(//, $$lastpicks), shuffle @picks;
print "pick $pick\n";
$$lastpicks =~ s/$pick//g;
$$lastpicks .= $pick;
$pick;
};
if( $$you =~ s/(?:$pick.)+// )
{
$$me .= $&;
}
else
{
print "GO FISH !!\n";
$$me .= substr $deck, 0, 2, '';
$more = 0;
}
}
elsif( $deck )
{
$$me .= substr $deck, 0, 2, '';
}
else
{
$more = 0;
}
}
arrange( $$me );
}
|
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).
|
#Crystal
|
Crystal
|
require "big"
def hamming(limit)
h = Array.new(limit, 1.to_big_i) # h = Array.new(limit+1, 1.to_big_i)
x2, x3, x5 = 2.to_big_i, 3.to_big_i, 5.to_big_i
i, j, k = 0, 0, 0
(1...limit).each do |n| # (1..limit).each do |n|
h[n] = Math.min(x2, Math.min(x3, x5))
x2 = 2 * h[i += 1] if x2 == h[n]
x3 = 3 * h[j += 1] if x3 == h[n]
x5 = 5 * h[k += 1] if x5 == h[n]
end
h[limit - 1]
end
start = Time.monotonic
print "Hamming Number (1..20): "; (1..20).each { |i| print "#{hamming(i)} " }
puts
puts "Hamming Number 1691: #{hamming 1691}"
puts "Hamming Number 1,000,000: #{hamming 1_000_000}"
puts "Elasped Time: #{(Time.monotonic - start).total_seconds} secs"
|
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
|
#Factor
|
Factor
|
USING: io random math math.parser kernel formatting ;
IN: guess-the-number
<PRIVATE
: gen-number ( -- n )
10 random 1 + ;
: make-guess ( n -- n ? )
dup readln string>number = ;
: play-game ( n -- n )
[ make-guess ]
[ "Guess a number between 1 and 10:" print flush ] do until ;
PRIVATE>
: guess-the-number ( -- )
gen-number play-game
"Yes, the number was %d!\n" printf ;
|
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
|
#Fantom
|
Fantom
|
class Main
{
public static Void main ()
{
Str target := (1..10).random.toStr
Str guess := ""
while (guess != target)
{
echo ("Enter a guess: ")
guess = Env.cur.in.readLine
if (guess.trim == target) // 'trim' to remove any spaces/newline
{
echo ("Well guessed!")
break
}
else
echo ("Failed - try again")
}
}
}
|
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.
|
#Elixir
|
Elixir
|
defmodule Greatest do
def subseq_sum(list) do
list_i = Enum.with_index(list)
acc = {0, 0, length(list), 0, 0}
{_,max,first,last,_} = Enum.reduce(list_i, acc, fn {elm,i},{curr,max,first,last,curr_first} ->
if curr < 0 do
if elm > max, do: {elm, elm, i, i, curr_first},
else: {elm, max, first, last, curr_first}
else
cur2 = curr + elm
if cur2 > max, do: {cur2, cur2, curr_first, i, curr_first},
else: {cur2, max, first, last, curr_first}
end
end)
{max, Enum.slice(list, first..last)}
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.
|
#ERRE
|
ERRE
|
PROGRAM MAX_SUM
DIM A%[11],B%[10],C%[4]
!$DYNAMIC
DIM P%[0]
PROCEDURE MAX_SUBSEQUENCE(P%[],N%->A$)
LOCAL A%,B%,I%,J%,M%,S%
A%=1
FOR I%=0 TO N% DO
S%=0
FOR J%=I% TO N% DO
S%+=P%[J%]
IF S%>M% THEN
M%=S%
A%=I%
B%=J%
END IF
END FOR
END FOR
IF A%>B% THEN A$="[]" EXIT PROCEDURE END IF
A$="["
FOR I%=A% TO B% DO
A$+=STR$(P%[I%])+","
END FOR
A$=LEFT$(A$,LEN(A$)-1)+"]"
END PROCEDURE
PROCEDURE SHOW_ARRAY(P%[],N%->A$)
LOCAL I%
A$="["
FOR I%=0 TO N% DO
A$+=STR$(P%[I%])+","
END FOR
A$=LEFT$(A$,LEN(A$)-1)+"]"
END PROCEDURE
BEGIN
A%[]=(0,1,2,-3,3,-1,0,-4,0,-1,-4,2)
N%=UBOUND(A%,1)
!$DIM P%[N%]
SHOW_ARRAY(A%[],N%->A$)
PRINT(A$;" -> ";)
MAX_SUBSEQUENCE(A%[],N%->A$)
PRINT(A$)
!$ERASE P%
B%[]=(-1,-2,3,5,6,-2,-1,4,-4,2,-1)
N%=UBOUND(B%,1)
!$DIM P%[N%]
SHOW_ARRAY(B%[],N%->A$)
PRINT(A$;" -> ";)
MAX_SUBSEQUENCE(B%[],N%->A$)
PRINT(A$)
!$ERASE P%
C%[]=(-1,-2,-3,-4,-5)
N%=UBOUND(C%,1)
!$DIM P%[N%]
SHOW_ARRAY(C%[],N%->A$)
PRINT(A$;" -> ";)
MAX_SUBSEQUENCE(C%[],N%->A$)
PRINT(A$)
!$ERASE P%
END PROGRAM
|
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)
|
#D
|
D
|
import std.stdio, std.random, std.typecons, std.conv, std.string,
std.range;
void main() {
immutable interval = tuple(1, 100);
writefln("Guess my target number that is between " ~
"%d and %d (inclusive).\n", interval[]);
immutable target = uniform!"[]"(interval[]);
foreach (immutable i; sequence!q{n}) {
writef("Your guess #%d: ", i + 1);
immutable txt = stdin.readln.strip;
Nullable!int answer;
try {
answer = txt.to!int;
} catch (ConvException e) {
writefln(" I don't understand your input '%s'", txt);
continue;
}
if (answer < interval[0] || answer > interval[1]) {
writeln(" Out of range!");
continue;
}
if (answer == target) {
writeln(" Well guessed.");
break;
}
writeln(answer < target ? " Too low." : " Too high.");
}
}
|
http://rosettacode.org/wiki/Greyscale_bars/Display
|
Greyscale bars/Display
|
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right hand side of the display. (This gives a total of 8 bars)
For the second quarter down, we start with white and step down through 14 shades of gray, getting darker until we have black on the right hand side of the display. (This gives a total of 16 bars).
Halfway down the display, we start with black, and produce 32 bars, ending in white, and for the last quarter, we start with white and step through 62 shades of grey, before finally arriving at black in the bottom right hand corner, producing a total of 64 bars for the bottom quarter.
|
#Scala
|
Scala
|
import scala.swing._
class GreyscaleBars extends Component {
override def paintComponent(g:Graphics2D)={
val barHeight=size.height>>2
for(run <- 0 to 3; colCount=8<<run){
val deltaX=size.width.toDouble/colCount
val colBase=if (run%2==0) -255 else 0
for(x <- 0 until colCount){
val col=(colBase+(255.0/(colCount-1)*x).toInt).abs
g.setColor(new Color(col,col,col))
val startX=(deltaX*x).toInt
val endX=(deltaX*(x+1)).toInt
g.fillRect(startX, barHeight*run, endX-startX, barHeight)
}
}
}
}
|
http://rosettacode.org/wiki/Greyscale_bars/Display
|
Greyscale bars/Display
|
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right hand side of the display. (This gives a total of 8 bars)
For the second quarter down, we start with white and step down through 14 shades of gray, getting darker until we have black on the right hand side of the display. (This gives a total of 16 bars).
Halfway down the display, we start with black, and produce 32 bars, ending in white, and for the last quarter, we start with white and step through 62 shades of grey, before finally arriving at black in the bottom right hand corner, producing a total of 64 bars for the bottom quarter.
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
include "draw.s7i";
include "keybd.s7i";
const proc: main is func
local
var integer: barHeight is 0;
var integer: barNumber is 0;
var integer: colCount is 0;
var integer: deltaX is 0;
var integer: x is 0;
var integer: col is 0;
begin
screen(640, 480);
KEYBOARD := GRAPH_KEYBOARD;
barHeight := height(curr_win) div 4;
for barNumber range 0 to 3 do
colCount := 8 << barNumber;
deltaX := width(curr_win) div colCount;
for x range 0 to pred(colCount) do
if barNumber rem 2 = 0 then
col := 65535 - 65535 div pred(colCount) * x;
else
col := 65535 div pred(colCount) * x;
end if;
rect(deltaX * x, barHeight * barNumber, deltaX, barHeight,
color(col, col, col));
end for;
end for;
ignore(getc(KEYBOARD));
end func;
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
|
Guess the number/With feedback (player)
|
Task
Write a player for the game that follows the following rules:
The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the scorer scores, in turn, until the computer correctly guesses the target number.
The computer should guess intelligently based on the accumulated scores given. One way is to use a Binary search based algorithm.
Related tasks
Guess the number/With Feedback
Bulls and cows/Player
|
#Perl
|
Perl
|
#!/usr/bin/perl
my $min = 1;
my $max = 99;
my $guess = int(rand $max) + $min;
my $tries = 0;
print "=>> Think of a number between $min and $max and I'll guess it!\n
Press <ENTER> when are you ready... ";
<STDIN>;
{
do {
$tries++;
print "\n=>> My guess is: $guess Is your number higher, lower, or equal? (h/l/e)\n> ";
my $score = <STDIN>;
if ($max <= $min) {
print "\nI give up...\n" and last;
} elsif ($score =~ /^h/i) {
$min = $guess + 1;
} elsif ($score =~ /^l/i) {
$max = $guess;
} elsif ($score =~ /^e/i) {
print "\nI knew it! It took me only $tries tries.\n" and last;
} else {
print "error: invalid score\n";
}
$guess = int(($max + $min) / 2);
} while(1);
}
|
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
|
#Elena
|
Elena
|
import extensions;
import system'collections;
import system'routines;
isHappy(int n)
{
auto cache := new List<int>(5);
int sum := 0;
int num := n;
while (num != 1)
{
if (cache.indexOfElement:num != -1)
{
^ false
};
cache.append(num);
while (num != 0)
{
int digit := num.mod:10;
sum += (digit*digit);
num /= 10
};
num := sum;
sum := 0
};
^ true
}
public program()
{
auto happynums := new List<int>(8);
int num := 1;
while (happynums.Length < 8)
{
if (isHappy(num))
{
happynums.append(num)
};
num += 1
};
console.printLine("First 8 happy numbers: ", happynums.asEnumerable())
}
|
http://rosettacode.org/wiki/Haversine_formula
|
Haversine formula
|
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes.
It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles".
Task
Implement a great-circle distance function, or use a library function,
to show the great-circle distance between:
Nashville International Airport (BNA) in Nashville, TN, USA, which is:
N 36°7.2', W 86°40.2' (36.12, -86.67) -and-
Los Angeles International Airport (LAX) in Los Angeles, CA, USA, which is:
N 33°56.4', W 118°24.0' (33.94, -118.40)
User Kaimbridge clarified on the Talk page:
-- 6371.0 km is the authalic radius based on/extracted from surface area;
-- 6372.8 km is an approximation of the radius of the average circumference
(i.e., the average great-elliptic or great-circle radius), where the
boundaries are the meridian (6367.45 km) and the equator (6378.14 km).
Using either of these values results, of course, in differing distances:
6371.0 km -> 2886.44444283798329974715782394574671655 km;
6372.8 km -> 2887.25995060711033944886005029688505340 km;
(results extended for accuracy check: Given that the radii are only
approximations anyways, .01' ≈ 1.0621333 km and .001" ≈ .00177 km,
practical precision required is certainly no greater than about
.0000001——i.e., .1 mm!)
As distances are segments of great circles/circumferences, it is
recommended that the latter value (r = 6372.8 km) be used (which
most of the given solutions have already adopted, anyways).
Most of the examples below adopted Kaimbridge's recommended value of
6372.8 km for the earth radius. However, the derivation of this
ellipsoidal quadratic mean radius
is wrong (the averaging over azimuth is biased). When applying these
examples in real applications, it is better to use the
mean earth radius,
6371 km. This value is recommended by the International Union of
Geodesy and Geophysics and it minimizes the RMS relative error between the
great circle and geodesic distance.
|
#PARI.2FGP
|
PARI/GP
|
dist(th1, th2, ph)={
my(v=[cos(ph)*cos(th1)-cos(th2),sin(ph)*cos(th1),sin(th1)-sin(th2)]);
asin(sqrt(norml2(v))/2)
};
distEarth(th1, ph1, th2, ph2)={
my(d=12742, deg=Pi/180); \\ Authalic diameter of the Earth
d*dist(th1*deg, th2*deg, (ph1-ph2)*deg)
};
distEarth(36.12, -86.67, 33.94, -118.4)
|
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
|
#Glee
|
Glee
|
"Hello world!"
|
http://rosettacode.org/wiki/Harshad_or_Niven_series
|
Harshad or Niven series
|
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is to create a function/method/procedure to generate successive members of the Harshad sequence.
Use it to:
list the first 20 members of the sequence, and
list the first Harshad number greater than 1000.
Show your output here.
Related task
Increasing gaps between consecutive Niven numbers
See also
OEIS: A005349
|
#PILOT
|
PILOT
|
C :n=0
:i=0
*first20
U :*harshad
C :i=i+1
T :#i: #n
J (i<20):*first20
C :n=1000
U :*harshad
T :First Harshad number greater than 1000: #n
E :
*harshad
C :n=n+1
:r=n
:s=0
*digit
C :a=r/10
:s=s+(r-a*10)
:r=a
J (r):*digit
J (n<>s*(n/s)):*harshad
E :
|
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
|
#Kotlin
|
Kotlin
|
import java.awt.*
import javax.swing.*
fun main(args: Array<String>) {
JOptionPane.showMessageDialog(null, "Goodbye, World!") // in alert box
with(JFrame("Goodbye, World!")) { // on title bar
layout = FlowLayout()
add(JButton("Goodbye, World!")) // on button
add(JTextArea("Goodbye, World!")) // in editable area
pack()
defaultCloseOperation = JFrame.EXIT_ON_CLOSE
isVisible = true
}
}
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Run_BASIC
|
Run BASIC
|
dim dd$(5) ' drop down box
for i = 1 to 5
dd$(i) = "Drop ";i
next i
value$ = "1234"
notes$ = "Rosetta Code
is good"
bf$ = "<SPAN STYLE='font-family:arial; font-weight:700; font-size:12pt'>"
[screen]
cls
html bf$;"<center><TABLE BORDER=1 CELLPADDING=0 CELLSPACING=0 bgcolor=wheat>"
html "<TR align=center BGCOLOR=tan><TD colspan=2>Rosetta Code</TD></TR><TR>"
html "<TD align=right bgcolor=tan>Value:</TD><TD>"
textbox #val,value$,5
html "</TD></TR><TR><TD bgcolor=tan align=right>Radio</TD><TD>"
radiogroup #rdo,"1,2,3,4,5",rdo$
#rdo horizontal(1)
html "</TD></TR><TR><TD bgcolor=tan align=right>Drop Down</TD><TD>"
listbox #dd,dd$(),1
html "</TD></TR><TR><TD bgcolor=tan align=right>Notes</TD><TD>"
textarea #notes,notes$,25,3
html "</TD></TR><TR bgcolor=tan><TD colspan=2 ALIGN=CENTER>"
button #inc, "Increment", [incr]
button #rnd, "Random", [rand]
button #ex, "Exit", [exit]
html "</TD></TR></TABLE>"
wait
[incr]
value = val(#val contents$())
value$ = str$(value + 1)
goto [screen]
[rand]
value$ = str$(int(rnd(1) * 10000))
goto [screen]
[exit]
print "Bye"
end
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Scala
|
Scala
|
import scala.swing._
import scala.swing.Swing._
import scala.swing.event._
object Interact extends SimpleSwingApplication {
def top = new MainFrame {
title = "Rosetta Code >>> Task: component interaction | Language: Scala"
val numberField = new TextField {
text = "0" // start at 0
horizontalAlignment = Alignment.Right
}
val incButton = new Button { text = "Increment" }
val randButton = new Button { text = "Random" }
// arrange buttons in a grid with 1 row, 2 columns
val buttonPanel = new GridPanel(1, 2) {
contents ++= List(incButton, randButton)
}
// arrange text field and button panel in a grid with 2 row, 1 column
contents = new GridPanel(2, 1) { contents ++= List(numberField, buttonPanel) }
// listen for keys pressed in numberField and button clicks
listenTo(numberField.keys, incButton, randButton)
reactions += {
case kt: KeyTyped if (!kt.char.isDigit) => // if the entered char isn't a digit …
kt.consume // … eat the event (i.e. stop it from being processed)
case ButtonClicked(`incButton`) =>
if (numberField.text.isEmpty) numberField.text = "0"
// we use BigInt to avoid long overflow/number format exception
numberField.text = (BigInt(numberField.text) + 1).toString
case ButtonClicked(`randButton`) =>
import Dialog._
numberField.text = showOptions(buttonPanel, message = "Are you sure?",
title = "Choose an option!", entries = List("Yes", "No", "Cancel"),
initial = 2) match {
case Result.Yes => (Long.MaxValue * math.random).toLong.toString
case _ => numberField.text
}
}
centerOnScreen()
}
}
|
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.
|
#BBC_BASIC
|
BBC BASIC
|
INSTALL @lib$+"STRINGLIB"
PRINT " Decimal Binary Gray Decoded"
FOR number% = 0 TO 31
gray% = FNgrayencode(number%)
PRINT number% " " FN_tobase(number%, 2, 5) ;
PRINT " " FN_tobase(gray%, 2, 5) FNgraydecode(gray%)
NEXT
END
DEF FNgrayencode(B%) = B% EOR (B% >>> 1)
DEF FNgraydecode(G%) : LOCAL B%
REPEAT B% EOR= G% : G% = G% >>> 1 : UNTIL G% = 0
= 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.
|
#bc
|
bc
|
scale = 0 /* to use integer division */
/* encode Gray code */
define e(i) {
auto h, r
if (i <= 0) return 0
h = i / 2
r = e(h) * 2 /* recurse */
if (h % 2 != i % 2) r += 1 /* xor low bits of h, i */
return r
}
/* decode Gray code */
define d(i) {
auto h, r
if (i <= 0) return 0
h = d(i / 2) /* recurse */
r = h * 2
if (h % 2 != i % 2) r += 1 /* xor low bits of h, i */
return r
}
/* print i as 5 binary digits */
define p(i) {
auto d, d[]
for (d = 0; d <= 4; d++) {
d[d] = i % 2
i /= 2
}
for (d = 4; d >= 0; d--) {
if(d[d] == 0) "0"
if(d[d] == 1) "1"
}
}
for (i = 0; i < 32; i++) {
/* original */ t = p(i); " => "
/* encoded */ e = e(i); t = p(e); " => "
/* decoded */ d = d(e); t = p(d); "
"
}
quit
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#Batch_File
|
Batch File
|
@echo off
setlocal enabledelayedexpansion
:: Without storing the output of the command, it can be viewed by inputting the command
dir
:: Storing the output of 'dir' as "line[]" containing the respective lines of output (starting at line[1])
:: Note: This method removes any empty lines from the output
set tempcount=0
for /f "tokens=*" %%i in ('dir') do (
set /a tempcount+=1
set "line!tempcount!=%%i"
)
:: The array would be viewed like this
for /l %%i in (1,1,%tempcount%) do echo !line%%i!
:: Storing the output of 'dir' in a file, then outputting the contents of the file to the screen
:: NOTE: rewrites any file named "out.temp" in the current directory
dir>out.temp
type out.temp
del out.temp
pause>nul
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#Bracmat
|
Bracmat
|
(system=
.sys$(str$(!arg " > temp"))&get$(temp,STR)
);
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#C
|
C
|
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char **argv)
{
if (argc < 2) return 1;
FILE *fd;
fd = popen(argv[1], "r");
if (!fd) return 1;
char buffer[256];
size_t chread;
/* String to store entire command contents in */
size_t comalloc = 256;
size_t comlen = 0;
char *comout = malloc(comalloc);
/* Use fread so binary data is dealt with correctly */
while ((chread = fread(buffer, 1, sizeof(buffer), fd)) != 0) {
if (comlen + chread >= comalloc) {
comalloc *= 2;
comout = realloc(comout, comalloc);
}
memmove(comout + comlen, buffer, chread);
comlen += chread;
}
/* We can now work with the output as we please. Just print
* out to confirm output is as expected */
fwrite(comout, 1, comlen, stdout);
free(comout);
pclose(fd);
return 0;
}
|
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!
|
#360_Assembly
|
360 Assembly
|
SWAP CSECT , control section start
BAKR 14,0 stack caller's registers
LR 12,15 entry point address to reg.12
USING SWAP,12 use as base
MVC A,=C'5678____' init field A
MVC B,=C'____1234' init field B
LA 2,L address of length field in reg.2
WTO TEXT=(2) Write To Operator, results in:
* +5678________1234
XC A,B XOR A,B
XC B,A XOR B,A
XC A,B XOR A,B. A holds B, B holds A
WTO TEXT=(2) Write To Operator, results in:
* +____12345678____
PR , return to caller
LTORG , literals displacement
L DC H'16' halfword containg decimal 16
A DS CL8 field A, 8 bytes
B DS CL8 field B, 8 bytes
END SWAP program 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.
|
#APL
|
APL
|
LIST←2 4 6 3 8
⌈/LIST
|
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.
|
#Action.21
|
Action!
|
CARD FUNC Gcd(CARD a,b)
CARD tmp
IF a<b THEN
tmp=a a=b b=tmp
FI
WHILE b#0
DO
tmp=a MOD b
a=b
b=tmp
OD
RETURN(a)
PROC Test(CARD a,b)
CARD res
res=Gcd(a,b)
PrintF("GCD of %I and %I is %I%E",a,b,res)
RETURN
PROC Main()
Test(48,18)
Test(9360,12240)
Test(17,19)
Test(123,1)
Test(0,0)
RETURN
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#C.23
|
C#
|
using System.Collections.Generic;
using System.IO;
class Program {
static void Main() {
var files = new List<string> {
"test1.txt",
"test2.txt"
};
foreach (string file in files) {
File.WriteAllText(file, File.ReadAllText(file).Replace("Goodbye London!", "Hello New York!"));
}
}
}
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#C.2B.2B
|
C++
|
#include <fstream>
#include <iterator>
#include <boost/regex.hpp>
#include <string>
#include <iostream>
int main( int argc , char *argv[ ] ) {
boost::regex to_be_replaced( "Goodbye London\\s*!" ) ;
std::string replacement( "Hello New York!" ) ;
for ( int i = 1 ; i < argc ; i++ ) {
std::ifstream infile ( argv[ i ] ) ;
if ( infile ) {
std::string filetext( (std::istreambuf_iterator<char>( infile )) ,
std::istreambuf_iterator<char>( ) ) ;
std::string changed ( boost::regex_replace( filetext , to_be_replaced , replacement )) ;
infile.close( ) ;
std::ofstream outfile( argv[ i ] , std::ios_base::out | std::ios_base::trunc ) ;
if ( outfile.is_open( ) ) {
outfile << changed ;
outfile.close( ) ;
}
}
else
std::cout << "Can't find file " << argv[ i ] << " !\n" ;
}
return 0 ;
}
|
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).
|
#ALGOL-M
|
ALGOL-M
|
BEGIN
INTEGER N, LEN, YES, NO, LIMIT, LONGEST, NLONG;
% RETURN P MOD Q %
INTEGER FUNCTION MOD(P, Q);
INTEGER P, Q;
BEGIN
MOD := P - Q * (P / Q);
END;
% COMPUTE AND OPTIONALLY DISPLAY HAILSTONE SEQUENCE FOR N. %
% RETURN LENGTH OF SEQUENCE OR ZERO ON OVERFLOW. %
INTEGER FUNCTION HAILSTONE(N, DISPLAY);
INTEGER N, DISPLAY;
BEGIN
INTEGER LEN;
LEN := 1;
IF DISPLAY = 1 THEN WRITE("");
WHILE (N <> 1) AND (N > 0) DO
BEGIN
IF DISPLAY = 1 THEN WRITEON(N," ");
IF MOD(N,2) = 0 THEN
N := N / 2
ELSE
N := (N * 3) + 1;
LEN := LEN + 1;
END;
IF DISPLAY = 1 THEN WRITEON(N);
HAILSTONE := (IF N < 0 THEN 0 ELSE LEN);
END;
% EXERCISE THE FUNCTION %
YES := 1; NO := 0;
WRITE("DISPLAY HAILSTONE SEQUENCE FOR WHAT NUMBER?");
READ(N);
LEN := HAILSTONE(N, YES);
WRITE("SEQUENCE LENGTH =", LEN);
% FIND LONGEST SEQUENCE BEFORE OVERFLOW %
N := 2;
LONGEST := 1;
LEN := 2;
NLONG := 2;
LIMIT := 1000;
WRITE("SEARCHING FOR LONGEST SEQUENCE UP TO N =",LIMIT," ...");
WHILE (N < LIMIT) AND (LEN <> 0) DO
BEGIN
LEN := HAILSTONE(N, NO);
IF LEN > LONGEST THEN
BEGIN
LONGEST := LEN;
NLONG := N;
END;
N := N + 1;
END;
IF LEN = 0 THEN WRITE("SEARCH TERMINATED WITH OVERFLOW AT N =",N-1);
WRITE("MAXIMUM SEQUENCE LENGTH =", LONGEST, " FOR N =", NLONG);
END
|
http://rosettacode.org/wiki/Grayscale_image
|
Grayscale image
|
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color use the formula recommended by CIE:
L = 0.2126 × R + 0.7152 × G + 0.0722 × B
When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
|
#Haskell
|
Haskell
|
module Bitmap.Gray(module Bitmap.Gray) where
import Bitmap
import Control.Monad.ST
newtype Gray = Gray Int deriving (Eq, Ord)
instance Color Gray where
luminance (Gray x) = x
black = Gray 0
white = Gray 255
toNetpbm = map $ toEnum . luminance
fromNetpbm = map $ Gray . fromEnum
netpbmMagicNumber _ = "P5"
netpbmMaxval _ = "255"
toGrayImage :: Color c => Image s c -> ST s (Image s Gray)
toGrayImage = mapImage $ Gray . luminance
|
http://rosettacode.org/wiki/Grayscale_image
|
Grayscale image
|
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color use the formula recommended by CIE:
L = 0.2126 × R + 0.7152 × G + 0.0722 × B
When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
|
#J
|
J
|
NB. converts the image to grayscale according to formula
NB. L = 0.2126*R + 0.7152*G + 0.0722*B
toGray=: [: <. +/ .*"1&0.2126 0.7152 0.0722
NB. converts grayscale image to the color image, with all channels equal
toColor=: 3 & $"0
|
http://rosettacode.org/wiki/Go_Fish
|
Go Fish
|
Write a program to let the user play Go Fish against a computer opponent. Use the following rules:
Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more.
If the opponent has any cards of the named rank, they must hand over all such cards, and the requester can ask again.
If the opponent has no cards of the named rank, the requester draws a card and ends their turn.
A book is a collection of every card of a given rank. Whenever a player completes a book, they may remove it from their hand.
If at any time a player's hand is empty, they may immediately draw a new card, so long as any new cards remain in the deck.
The game ends when every book is complete. The player with the most books wins.
The game's AI need not be terribly smart, but it should use at least some strategy. That is, it shouldn't choose legal moves entirely at random.
You may want to use code from Playing Cards.
Related tasks:
Playing cards
Card shuffles
Deal cards_for_FreeCell
War Card_Game
Poker hand_analyser
|
#Julia
|
Julia
|
#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Go_Fish
use warnings;
use List::Util qw( first shuffle );
my $pat = qr/[atjqk2-9]/; # ranks
my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) }
qw( a t j q k ), 2 .. 9;
my $mebooks = my $youbooks = 0;
my $me = substr $deck, 0, 2 * 9, '';
my $mepicks = join '', $me =~ /$pat/g;
arrange($me);
$mebooks++ while $me =~ s/($pat).\1.\1.\1.//;
my $you = substr $deck, 0, 2 * 9, '';
my $youpicks = join '', $you =~ /$pat/g;
arrange($you);
$youbooks++ while $you =~ s/($pat).\1.\1.\1.//;
while( $mebooks + $youbooks < 13 )
{
play( \$you, \$youbooks, \$youpicks, \$me, \$mebooks, 1 );
$mebooks + $youbooks == 13 and last;
play( \$me, \$mebooks, \$mepicks, \$you, \$youbooks, 0 );
}
print "me $mebooks you $youbooks\n";
sub arrange { $_[0] = join '', sort $_[0] =~ /../g }
sub human
{
my $have = shift =~ s/($pat).\K(?!\1)/ /gr;
local $| = 1;
my $pick;
do
{
print "You have $have, enter request: ";
($pick) = lc(<STDIN>) =~ /$pat/g;
} until $pick and $have =~ /$pick/;
return $pick;
}
sub play
{
my ($me, $mb, $lastpicks, $you, $yb, $human) = @_;
my $more = 1;
while( arrange( $$me ), $more and $$mb + $$yb < 13 )
{
# use Data::Dump 'dd'; dd \@_, "deck $deck";
if( $$me =~ s/($pat).\1.\1.\1.// )
{
print "book of $&\n";
$$mb++;
}
elsif( $$me )
{
my $pick = $human ? do { human($$me) } : do
{
my %picks;
$picks{$_}++ for my @picks = $$me =~ /$pat/g;
my $pick = first { $picks{$_} } split(//, $$lastpicks), shuffle @picks;
print "pick $pick\n";
$$lastpicks =~ s/$pick//g;
$$lastpicks .= $pick;
$pick;
};
if( $$you =~ s/(?:$pick.)+// )
{
$$me .= $&;
}
else
{
print "GO FISH !!\n";
$$me .= substr $deck, 0, 2, '';
$more = 0;
}
}
elsif( $deck )
{
$$me .= substr $deck, 0, 2, '';
}
else
{
$more = 0;
}
}
arrange( $$me );
}
|
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).
|
#D
|
D
|
import std.stdio, std.bigint, std.algorithm, std.range, core.memory;
auto hamming(in uint n) pure nothrow /*@safe*/ {
immutable BigInt two = 2, three = 3, five = 5;
auto h = new BigInt[n];
h[0] = 1;
BigInt x2 = 2, x3 = 3, x5 = 5;
size_t i, j, k;
foreach (ref el; h.dropOne) {
el = min(x2, x3, x5);
if (el == x2) x2 = two * h[++i];
if (el == x3) x3 = three * h[++j];
if (el == x5) x5 = five * h[++k];
}
return h.back;
}
void main() {
GC.disable;
iota(1, 21).map!hamming.writeln;
1_691.hamming.writeln;
1_000_000.hamming.writeln;
}
|
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
|
#Forth
|
Forth
|
\ tested with GForth 0.7.0
: RND ( -- n) TIME&DATE 2DROP 2DROP DROP 10 MOD ; \ crude random number
: ASK ( -- ) CR ." Guess a number between 1 and 10? " ;
: GUESS ( -- n) PAD DUP 4 ACCEPT EVALUATE ;
: REPLY ( n n' -- n) 2DUP <> IF CR ." No, it's not " DUP . THEN ;
: GAME ( -- )
RND
BEGIN ASK GUESS REPLY OVER = UNTIL
CR ." Yes it was " .
CR ." Good guess!" ;
|
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
|
#Fortran
|
Fortran
|
program guess_the_number
implicit none
integer :: guess
real :: r
integer :: i, clock, count, n
integer,dimension(:),allocatable :: seed
real,parameter :: rmax = 10
!initialize random number generator:
call random_seed(size=n)
allocate(seed(n))
call system_clock(count)
seed = count
call random_seed(put=seed)
deallocate(seed)
!pick a random number between 1 and rmax:
call random_number(r) !r between 0.0 and 1.0
i = int((rmax-1.0)*r + 1.0) !i between 1 and rmax
!get user guess:
write(*,'(A)') 'I''m thinking of a number between 1 and 10.'
do !loop until guess is correct
write(*,'(A)',advance='NO') 'Enter Guess: '
read(*,'(I5)') guess
if (guess==i) exit
write(*,*) 'Sorry, try again.'
end do
write(*,*) 'You''ve guessed my number!'
end program guess_the_number
|
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.
|
#Euler_Math_Toolbox
|
Euler Math Toolbox
|
>function %maxsubs (v,n) ...
$if n==1 then
$ if (v[1]<0) then return {zeros(1,0),zeros(1,0)}
$ else return {v,v};
$ endif;
$endif;
${v1,v2}=%maxsubs(v[1:n-1],n-1);
$m1=sum(v1); m2=sum(v2); m3=m2+v[n];
$if m3>0 then v3=v2|v[n]; else v3=zeros(1,0); endif;
$if m3>m1 then return {v2|v[n],v3};
$else return {v1,v3};
$endif;
$endfunction
>function maxsubs (v) ...
${v1,v2}=%maxsubs(v,cols(v));
$return v1
$endfunction
>maxsubs([0, 1, 2, -3, 3, -1, 0, -4, 0, -1, -4])
[ 0 1 2 ]
>maxsubs([-1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1])
[ 3 5 6 -2 -1 4 ]
>maxsubs([-1, -2, -3, -4, -5])
Empty matrix of size 1x0
|
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.
|
#Euphoria
|
Euphoria
|
function maxSubseq(sequence s)
integer sum, maxsum, first, last
maxsum = 0
first = 1
last = 0
for i = 1 to length(s) do
sum = 0
for j = i to length(s) do
sum += s[j]
if sum > maxsum then
maxsum = sum
first = i
last = j
end if
end for
end for
return s[first..last]
end function
? maxSubseq({-1, -2, 3, 5, 6, -2, -1, 4, -4, 2, -1})
? maxSubseq({})
? maxSubseq({-1, -5, -3})
|
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)
|
#DCL
|
DCL
|
$ rnd = f$extract( 21, 2, f$time() )
$ count = 0
$ loop:
$ inquire guess "guess what number between 0 and 99 inclusive I am thinking of"
$ guess = f$integer( guess )
$ if guess .lt. 0 .or. guess .gt. 99
$ then
$ write sys$output "out of range"
$ goto loop
$ endif
$ count = count + 1
$ if guess .lt. rnd then $ write sys$output "too small"
$ if guess .gt. rnd then $ write sys$output "too large"
$ if guess .ne. rnd then $ goto loop
$ write sys$output "it only took you ", count, " guesses"
|
http://rosettacode.org/wiki/Greyscale_bars/Display
|
Greyscale bars/Display
|
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right hand side of the display. (This gives a total of 8 bars)
For the second quarter down, we start with white and step down through 14 shades of gray, getting darker until we have black on the right hand side of the display. (This gives a total of 16 bars).
Halfway down the display, we start with black, and produce 32 bars, ending in white, and for the last quarter, we start with white and step through 62 shades of grey, before finally arriving at black in the bottom right hand corner, producing a total of 64 bars for the bottom quarter.
|
#Tcl
|
Tcl
|
package require Tcl 8.5
package require Tk 8.5
wm attributes . -fullscreen 1
pack [canvas .c -highlightthick 0] -fill both -expand 1
# Add more values into this to do more greyscale bar variations
set splits {8 16 32 64}
set dy [expr {[winfo screenheight .c] / [llength $splits]}]
set y 0
foreach s $splits {
set dx [expr {double([winfo screenwidth .c]) / $s}]
set dc [expr {double(0xFF) / ($s-1)}]
for {set i 0} {$i < $s} {incr i} {
set c [expr {int($i * $dc)}]
set x [expr {int($i * $dx)}]
.c create rectangle $x $y [expr {$x+$dx+1}] [expr {$y+$dy+1}] \
-fill [format "#%02x%02x%02x" $c $c $c] -outline {}
}
incr y $dy
}
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
|
Guess the number/With feedback (player)
|
Task
Write a player for the game that follows the following rules:
The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the scorer scores, in turn, until the computer correctly guesses the target number.
The computer should guess intelligently based on the accumulated scores given. One way is to use a Binary search based algorithm.
Related tasks
Guess the number/With Feedback
Bulls and cows/Player
|
#Phix
|
Phix
|
--
-- demo\rosetta\Guess_the_number2.exw
--
with javascript_semantics -- (spacing not (yet) great...)
include pGUI.e
Ihandle lbl, guess, toohigh, too_low, correct, newgame, dlg
integer Min=0, Max=100, Guess
constant LTHINK = sprintf("Think of a number between %d and %d.",{Min,Max})
procedure set_active(bool bActive)
IupSetInt({toohigh, too_low, correct},"ACTIVE",bActive)
IupSetInt(newgame,"ACTIVE",not bActive)
end procedure
procedure set_guess()
Guess = floor((Max+Min)/2)
string title = sprintf("My guess is %d, is this too high, too low, or correct?", Guess)
if Max<Min then
set_active(false)
title = "I think something is strange here..."
end if
IupSetStrAttribute(guess,"TITLE",title)
IupRefresh(guess)
end procedure
function click_cb(Ihandle ih)
switch substitute(IupGetAttribute(ih,"TITLE"),"Too ","")[1] do
case 'H': Max = Guess-1 set_guess()
case 'L': Min = Guess+1 set_guess()
case 'C': IupSetStrAttribute(guess,"TITLE","I did it!")
set_active(false)
case 'N': Min = 0 Max = 100 set_guess()
set_active(true)
end switch
return IUP_DEFAULT
end function
procedure main()
IupOpen()
lbl = IupLabel(LTHINK)
guess = IupLabel("")
toohigh = IupButton("Too High", Icallback("click_cb"))
too_low = IupButton("Too Low", Icallback("click_cb"))
correct = IupButton("Correct", Icallback("click_cb"))
newgame = IupButton("New Game", Icallback("click_cb"), "ACTIVE=NO")
dlg = IupDialog(IupVbox({lbl,
guess,
IupHbox({toohigh,too_low,correct,newgame},
"GAP=10")},
`NMARGIN=15x15,GAP=10`),
`MINSIZE=300x100,TITLE="Guess the number2"`)
set_guess()
IupShow(dlg)
if platform()!=JS then
IupMainLoop()
IupClose()
end if
end procedure
main()
|
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
|
#Elixir
|
Elixir
|
defmodule Happy do
def task(num) do
Process.put({:happy, 1}, true)
Stream.iterate(1, &(&1+1))
|> Stream.filter(fn n -> happy?(n) end)
|> Enum.take(num)
end
defp happy?(n) do
sum = square_sum(n, 0)
val = Process.get({:happy, sum})
if val == nil do
Process.put({:happy, sum}, false)
val = happy?(sum)
Process.put({:happy, sum}, val)
end
val
end
defp square_sum(0, sum), do: sum
defp square_sum(n, sum) do
r = rem(n, 10)
square_sum(div(n, 10), sum + r*r)
end
end
IO.inspect Happy.task(8)
|
http://rosettacode.org/wiki/Haversine_formula
|
Haversine formula
|
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes.
It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles".
Task
Implement a great-circle distance function, or use a library function,
to show the great-circle distance between:
Nashville International Airport (BNA) in Nashville, TN, USA, which is:
N 36°7.2', W 86°40.2' (36.12, -86.67) -and-
Los Angeles International Airport (LAX) in Los Angeles, CA, USA, which is:
N 33°56.4', W 118°24.0' (33.94, -118.40)
User Kaimbridge clarified on the Talk page:
-- 6371.0 km is the authalic radius based on/extracted from surface area;
-- 6372.8 km is an approximation of the radius of the average circumference
(i.e., the average great-elliptic or great-circle radius), where the
boundaries are the meridian (6367.45 km) and the equator (6378.14 km).
Using either of these values results, of course, in differing distances:
6371.0 km -> 2886.44444283798329974715782394574671655 km;
6372.8 km -> 2887.25995060711033944886005029688505340 km;
(results extended for accuracy check: Given that the radii are only
approximations anyways, .01' ≈ 1.0621333 km and .001" ≈ .00177 km,
practical precision required is certainly no greater than about
.0000001——i.e., .1 mm!)
As distances are segments of great circles/circumferences, it is
recommended that the latter value (r = 6372.8 km) be used (which
most of the given solutions have already adopted, anyways).
Most of the examples below adopted Kaimbridge's recommended value of
6372.8 km for the earth radius. However, the derivation of this
ellipsoidal quadratic mean radius
is wrong (the averaging over azimuth is biased). When applying these
examples in real applications, it is better to use the
mean earth radius,
6371 km. This value is recommended by the International Union of
Geodesy and Geophysics and it minimizes the RMS relative error between the
great circle and geodesic distance.
|
#Pascal
|
Pascal
|
Program HaversineDemo(output);
uses
Math;
function haversineDist(th1, ph1, th2, ph2: double): double;
const
diameter = 2 * 6372.8;
var
dx, dy, dz: double;
begin
ph1 := degtorad(ph1 - ph2);
th1 := degtorad(th1);
th2 := degtorad(th2);
dz := sin(th1) - sin(th2);
dx := cos(ph1) * cos(th1) - cos(th2);
dy := sin(ph1) * cos(th1);
haversineDist := arcsin(sqrt(dx**2 + dy**2 + dz**2) / 2) * diameter;
end;
begin
writeln ('Haversine distance: ', haversineDist(36.12, -86.67, 33.94, -118.4):7:2, ' km.');
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
|
#Global_Script
|
Global Script
|
λ _. print qq{Hello world!\n}
|
http://rosettacode.org/wiki/Harshad_or_Niven_series
|
Harshad or Niven series
|
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is to create a function/method/procedure to generate successive members of the Harshad sequence.
Use it to:
list the first 20 members of the sequence, and
list the first Harshad number greater than 1000.
Show your output here.
Related task
Increasing gaps between consecutive Niven numbers
See also
OEIS: A005349
|
#PL.2FI
|
PL/I
|
*process source or(!) xref attributes;
niven: Proc Options(main);
/*********************************************************************
* 08-06.2013 Walter Pachl translated from Rexx
* with a slight improvement: Do j=y+1 By 1;
*********************************************************************/
Dcl (ADDR,HBOUND,MOD,SUBSTR,VERIFY) Builtin;
Dcl SYSPRINT Print;
Dcl (x,y) dec fixed(8);
x=20;
y=1000;
Begin;
Dcl (n(x),j) Dec Fixed(8);
Dcl ni Bin Fixed(31) Init(0);
Dcl result Char(100) Var Init('');
loop:
Do j=1 By 1;
If mod(j,sumdigs(j))=0 Then Do;
ni+=1;
n(ni)=j;
result=result!!' '!!d2c(j);
If ni=x Then Leave loop;
End;
End;
Put Edit('first 20 Niven numbers: ',result)(Skip,a,a);
Do j=y+1 By 1;
If mod(j,sumdigs(j))=0 Then
Leave;
End;
Put Edit('first Niven number > ',d2c(y),' is: ',d2c(j))(Skip,4(a));
End;
sumDigs: proc(z) Returns(Dec Fixed(3));
Dcl z Pic'(8)9';
Dcl d(8) Pic'9' Based(addr(z));
Dcl i Bin Fixed(31);
Dcl sd Dec Fixed(3) Init(0);
Do i=1 To hbound(d);
sd+=d(i);
End;
Return(sd);
End;
d2c: Proc(z) Returns(char(8) Var);
Dcl z Pic'(8)z';
Dcl p Bin Fixed(31);
p=verify(z,' ');
Return(substr(z,p));
End;
End;
|
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
|
#LabVIEW
|
LabVIEW
|
sys_process('/usr/bin/osascript', (: '-e', 'display dialog "Goodbye, World!"'))->wait
|
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
|
#Lasso
|
Lasso
|
sys_process('/usr/bin/osascript', (: '-e', 'display dialog "Goodbye, World!"'))->wait
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Smalltalk
|
Smalltalk
|
|top input vh incButton rndButton|
vh := ValueHolder with:0.
top := StandardSystemView label:'Rosetta GUI interaction'.
top extent:300@100.
top add:((Label label:'Value:') origin: 0 @ 10 corner: 100 @ 40).
top add:(input := EditField origin: 102 @ 10 corner: 1.0 @ 40).
input model:(TypeConverter onNumberValue:vh).
input acceptOnLostFocus:true; acceptOnReturn:true.
top add:((incButton := Button label:'Inc') origin: 10 @ 50 corner: 100 @ 80).
top add:((rndButton := Button label:'Rnd') origin: 110 @ 50 corner: 210 @ 80).
incButton action:[ vh value: (vh value + 1) ].
rndButton action:[ vh value: Random nextInteger ].
top open
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Tcl
|
Tcl
|
package require Tk
###--- Our data Model! ---###
# A single variable will do just fine
set field 0
###--- Lay out the GUI components in our View ---###
# We use the Ttk widget set here; it looks much better on Windows and OSX
# First, a quick hack to make things look even nicer
place [ttk::frame .bg] -relwidth 1 -relheight 1
# A labelled frame containing an entry field constrained to use numbers
pack [ttk::labelframe .val -text "Value"]
pack [ttk::entry .val.ue -textvariable field \
-validate key -invalidcommand bell \
-validatecommand {string is integer %P}]
# Now, a pair of buttons
pack [ttk::button .inc -text "increment" -command step]
pack [ttk::button .rnd -text "random" -command random]
###--- Now we define the behaviors, the Controller ---###
# How to respond to a click on the "increment" button
proc step {} {
global field
incr field
}
# How to respond to a click on the "random" button
proc random {} {
global field
if {[tk_messageBox -type yesno -parent . \
-message "Reset to random?"] eq "yes"} {
set field [expr {int(rand() * 5000)}]
}
}
|
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.
|
#C
|
C
|
int gray_encode(int n) {
return n ^ (n >> 1);
}
int gray_decode(int n) {
int p = n;
while (n >>= 1) p ^= n;
return p;
}
|
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.
|
#C.23
|
C#
|
using System;
public class Gray {
public static ulong grayEncode(ulong n) {
return n^(n>>1);
}
public static ulong grayDecode(ulong n) {
ulong i=1<<8*64-2; //long is 64-bit
ulong p, b=p=n&i;
while((i>>=1)>0)
b|=p=n&i^p>>1;
return b;
}
public static void Main(string[] args) {
Console.WriteLine("Number\tBinary\tGray\tDecoded");
for(ulong i=0;i<32;i++) {
Console.WriteLine(string.Format("{0}\t{1}\t{2}\t{3}", i, Convert.ToString((long)i, 2), Convert.ToString((long)grayEncode(i), 2), grayDecode(grayEncode(i))));
}
}
}
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#C.23
|
C#
|
using System;
namespace GetSystemCommandOutput {
class Program {
static void Main(string[] args) {
System.Diagnostics.Process process = new System.Diagnostics.Process();
System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
startInfo.FileName = "cmd.exe";
startInfo.Arguments = "/c echo Hello World";
startInfo.RedirectStandardOutput = true;
startInfo.UseShellExecute = false;
process.StartInfo = startInfo;
process.Start();
string output = process.StandardOutput.ReadToEnd();
Console.WriteLine("Output is {0}", output);
}
}
}
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#C.2B.2B
|
C++
|
#include <fstream>
#include <iostream>
std::string execute(const std::string& command) {
system((command + " > temp.txt").c_str());
std::ifstream ifs("temp.txt");
std::string ret{ std::istreambuf_iterator<char>(ifs), std::istreambuf_iterator<char>() };
ifs.close(); // must close the inout stream so the file can be cleaned up
if (std::remove("temp.txt") != 0) {
perror("Error deleting temporary file");
}
return ret;
}
int main() {
std::cout << execute("whoami") << '\n';
}
|
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!
|
#6502_Assembly
|
6502 Assembly
|
;swap X with Y
pha ;push accumulator
txa
pha ;push x
tya
pha ;push y
pla
tax ;pop y into x
pla
tay ;pop x into y
pla ;pop accumulator
|
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.
|
#AppleScript
|
AppleScript
|
max({1, 2, 3, 4, 20, 6, 11, 3, 9, 7})
on max(aList)
set _curMax to first item of aList
repeat with i in (rest of aList)
if i > _curMax then set _curMax to contents of i
end repeat
return _curMax
end max
|
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.
|
#ActionScript
|
ActionScript
|
//Euclidean algorithm
function gcd(a:int,b:int):int
{
var tmp:int;
//Swap the numbers so a >= b
if(a < b)
{
tmp = a;
a = b;
b = tmp;
}
//Find the gcd
while(b != 0)
{
tmp = a % b;
a = b;
b = tmp;
}
return a;
}
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#Clojure
|
Clojure
|
(defn hello-goodbye [& more]
(doseq [file more]
(spit file (.replace (slurp file) "Goodbye London!" "Hello New York!"))))
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#Common_Lisp
|
Common Lisp
|
(defun hello-goodbye (files)
(labels ((replace-from-file (file)
(with-open-file (in file)
(loop for line = (read-line in nil)
while line do
(loop for index = (search "Goodbye London!" line)
while index do
(setf (subseq line index) "Hello New York!"))
collecting line)))
(write-lines-to-file (lines file)
(with-open-file (out file :direction :output :if-exists :overwrite)
(dolist (line lines)
(write-line line out))))
(replace-in-file (file)
(write-lines-to-file (replace-from-file file) file)))
(map nil #'replace-in-file files)))
|
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).
|
#ALGOL_W
|
ALGOL W
|
begin
% show some Hailstone Sequence related information %
% calculates the length of the sequence generated by n, %
% if showFirstAndLast is true, the first and last 4 elements of the %
% sequence are stored in first and last %
% hs holds a cache of the upbHs previously calculated sequence lengths %
% if showFirstAndLast is false, the cache will be used %
procedure hailstone ( integer value n
; integer array first, last ( * )
; integer result length
; integer array hs ( * )
; integer value upbHs
; logical value showFirstAndLast
) ;
if not showFirstAndLast and n <= upbHs and hs( n ) not = 0 then begin
% no need to store the start and end of the sequence and we already %
% know the length of the sequence for n %
length := hs( n )
end
else begin
% must calculate the sequence length %
integer sv;
for i := 1 until 4 do first( i ) := last( i ) := 0;
length := 0;
sv := n;
if sv > 0 then begin
while begin
length := length + 1;
if showFirstAndLast then begin
if length <= 4 then first( length ) := sv;
for lPos := 1 until 3 do last( lPos ) := last( lPos + 1 );
last( 4 ) := sv
end
else if sv <= upbHs and hs( sv ) not = 0 then begin
% have a known value %
length := ( length + hs( sv ) ) - 1;
sv := 1
end ;
sv not = 1
end do begin
sv := if odd( sv ) then ( 3 * sv ) + 1 else sv div 2
end while_sv_ne_1 ;
if n < upbHs then hs( n ) := length
end if_sv_gt_0
end hailstone ;
begin
% test the hailstone procedure %
integer HS_CACHE_SIZE;
HS_CACHE_SIZE := 100000;
begin
integer array first, last ( 1 :: 4 );
integer length, maxLength, maxNumber;
integer array hs ( 1 :: HS_CACHE_SIZE );
for i := 1 until HS_CACHE_SIZE do hs( i ) := 0;
hailstone( 27, first, last, length, hs, HS_CACHE_SIZE, true );
write( i_w := 1, s_w := 0
, "27: length ", length, ", first: ["
, first( 1 ), " ", first( 2 ), " ", first( 3 ), " ", first( 4 )
, "] last: ["
, last( 1 ), " ", last( 2 ), " ", last( 3 ), " ", last( 4 )
, "]"
);
maxNumber := 0;
maxLength := 0;
for n := 1 until 100000 do begin
hailstone( n, first, last, length, hs, HS_CACHE_SIZE, false );
if length > maxLength then begin
maxNumber := n;
maxLength := length
end if_length_gt_maxLength
end for_n ;
write( i_w := 1, s_w := 1, "Maximum sequence length: ", maxLength, " for: ", maxNumber )
end
end
end.
|
http://rosettacode.org/wiki/Grayscale_image
|
Grayscale image
|
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color use the formula recommended by CIE:
L = 0.2126 × R + 0.7152 × G + 0.0722 × B
When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
|
#Java
|
Java
|
void convertToGrayscale(final BufferedImage image){
for(int i=0; i<image.getWidth(); i++){
for(int j=0; j<image.getHeight(); j++){
int color = image.getRGB(i,j);
int alpha = (color >> 24) & 255;
int red = (color >> 16) & 255;
int green = (color >> 8) & 255;
int blue = (color) & 255;
final int lum = (int)(0.2126 * red + 0.7152 * green + 0.0722 * blue);
alpha = (alpha << 24);
red = (lum << 16);
green = (lum << 8);
blue = lum;
color = alpha + red + green + blue;
image.setRGB(i,j,color);
}
}
}
|
http://rosettacode.org/wiki/Grayscale_image
|
Grayscale image
|
Many image processing algorithms are defined for grayscale (or else monochromatic) images.
Task
Extend the data storage type defined on this page to support grayscale images.
Define two operations, one to convert a color image to a grayscale image and one for the backward conversion.
To get luminance of a color use the formula recommended by CIE:
L = 0.2126 × R + 0.7152 × G + 0.0722 × B
When using floating-point arithmetic make sure that rounding errors would not cause run-time problems or else distorted results when calculated luminance is stored as an unsigned integer.
|
#JavaScript
|
JavaScript
|
function toGray(img) {
let cnv = document.getElementById("canvas");
let ctx = cnv.getContext('2d');
let imgW = img.width;
let imgH = img.height;
cnv.width = imgW;
cnv.height = imgH;
ctx.drawImage(img, 0, 0);
let pixels = ctx.getImageData(0, 0, imgW, imgH);
for (let y = 0; y < pixels.height; y ++) {
for (let x = 0; x < pixels.width; x ++) {
let i = (y * 4) * pixels.width + x * 4;
let avg = (pixels.data[i] + pixels.data[i + 1] + pixels.data[i + 2]) / 3;
pixels.data[i] = avg;
pixels.data[i + 1] = avg;
pixels.data[i + 2] = avg;
}
}
ctx.putImageData(pixels, 0, 0, 0, 0, pixels.width, pixels.height);
return cnv.toDataURL();
}
|
http://rosettacode.org/wiki/Go_Fish
|
Go Fish
|
Write a program to let the user play Go Fish against a computer opponent. Use the following rules:
Each player is dealt nine cards to start with.
On their turn, a player asks their opponent for a given rank (such as threes or kings). A player must already have at least one card of a given rank to ask for more.
If the opponent has any cards of the named rank, they must hand over all such cards, and the requester can ask again.
If the opponent has no cards of the named rank, the requester draws a card and ends their turn.
A book is a collection of every card of a given rank. Whenever a player completes a book, they may remove it from their hand.
If at any time a player's hand is empty, they may immediately draw a new card, so long as any new cards remain in the deck.
The game ends when every book is complete. The player with the most books wins.
The game's AI need not be terribly smart, but it should use at least some strategy. That is, it shouldn't choose legal moves entirely at random.
You may want to use code from Playing Cards.
Related tasks:
Playing cards
Card shuffles
Deal cards_for_FreeCell
War Card_Game
Poker hand_analyser
|
#Kotlin
|
Kotlin
|
#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Go_Fish
use warnings;
use List::Util qw( first shuffle );
my $pat = qr/[atjqk2-9]/; # ranks
my $deck = join '', shuffle map { my $rank = $_; map "$rank$_", qw( S H C D ) }
qw( a t j q k ), 2 .. 9;
my $mebooks = my $youbooks = 0;
my $me = substr $deck, 0, 2 * 9, '';
my $mepicks = join '', $me =~ /$pat/g;
arrange($me);
$mebooks++ while $me =~ s/($pat).\1.\1.\1.//;
my $you = substr $deck, 0, 2 * 9, '';
my $youpicks = join '', $you =~ /$pat/g;
arrange($you);
$youbooks++ while $you =~ s/($pat).\1.\1.\1.//;
while( $mebooks + $youbooks < 13 )
{
play( \$you, \$youbooks, \$youpicks, \$me, \$mebooks, 1 );
$mebooks + $youbooks == 13 and last;
play( \$me, \$mebooks, \$mepicks, \$you, \$youbooks, 0 );
}
print "me $mebooks you $youbooks\n";
sub arrange { $_[0] = join '', sort $_[0] =~ /../g }
sub human
{
my $have = shift =~ s/($pat).\K(?!\1)/ /gr;
local $| = 1;
my $pick;
do
{
print "You have $have, enter request: ";
($pick) = lc(<STDIN>) =~ /$pat/g;
} until $pick and $have =~ /$pick/;
return $pick;
}
sub play
{
my ($me, $mb, $lastpicks, $you, $yb, $human) = @_;
my $more = 1;
while( arrange( $$me ), $more and $$mb + $$yb < 13 )
{
# use Data::Dump 'dd'; dd \@_, "deck $deck";
if( $$me =~ s/($pat).\1.\1.\1.// )
{
print "book of $&\n";
$$mb++;
}
elsif( $$me )
{
my $pick = $human ? do { human($$me) } : do
{
my %picks;
$picks{$_}++ for my @picks = $$me =~ /$pat/g;
my $pick = first { $picks{$_} } split(//, $$lastpicks), shuffle @picks;
print "pick $pick\n";
$$lastpicks =~ s/$pick//g;
$$lastpicks .= $pick;
$pick;
};
if( $$you =~ s/(?:$pick.)+// )
{
$$me .= $&;
}
else
{
print "GO FISH !!\n";
$$me .= substr $deck, 0, 2, '';
$more = 0;
}
}
elsif( $deck )
{
$$me .= substr $deck, 0, 2, '';
}
else
{
$more = 0;
}
}
arrange( $$me );
}
|
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).
|
#Dart
|
Dart
|
import 'dart:math';
final lb2of2 = 1.0;
final lb2of3 = log(3.0) / log(2.0);
final lb2of5 = log(5.0) / log(2.0);
class Trival {
final double log2;
final int twos;
final int threes;
final int fives;
Trival mul2() {
return Trival(this.log2 + lb2of2, this.twos + 1, this.threes, this.fives);
}
Trival mul3() {
return Trival(this.log2 + lb2of3, this.twos, this.threes + 1, this.fives);
}
Trival mul5() {
return Trival(this.log2 + lb2of5, this.twos, this.threes, this.fives + 1);
}
@override String toString() {
return this.log2.toString() + " "
+ this.twos.toString() + " "
+ this.threes.toString() + " "
+ this.fives.toString();
}
const Trival(this.log2, this.twos, this.threes, this.fives);
}
Iterable<Trival> makeHammings() sync* {
var one = Trival(0.0, 0, 0, 0);
yield(one);
var s532 = one.mul2();
var mrg = one.mul3();
var s53 = one.mul3().mul3(); // equivalent to 9 for advance step
var s5 = one.mul5();
var i = -1; var j = -1;
List<Trival> h = [];
List<Trival> m = [];
Trival rslt;
while (true) {
if (s532.log2 < mrg.log2) {
rslt = s532; h.add(s532); ++i; s532 = h[i].mul2();
} else {
rslt = mrg; h.add(mrg);
if (s53.log2 < s5.log2) {
mrg = s53; m.add(s53); ++j; s53 = m[j].mul3();
} else {
mrg = s5; m.add(s5); s5 = s5.mul5();
}
if (j > (m.length >> 1)) {m.removeRange(0, j); j = 0; }
}
if (i > (h.length >> 1)) {h.removeRange(0, i); i = 0; }
yield(rslt);
}
}
BigInt trival2Int(Trival tv) {
return BigInt.from(2).pow(tv.twos)
* BigInt.from(3).pow(tv.threes)
* BigInt.from(5).pow(tv.fives);
}
void main() {
final numhams = 1000000000000;
var hamseqstr = "The first 20 Hamming numbers are: ( ";
makeHammings().take(20)
.forEach((h) => hamseqstr += trival2BigInt(h).toString() + " ");
print(hamseqstr + ")");
var nthhamseqstr = "The first 20 Hamming numbers are: ( ";
for (var i = 1; i <= 20; ++i) {
nthhamseqstr += trival2BigInt(nthHamming(i)).toString() + " ";
}
print(nthhamseqstr + ")");
final strt = DateTime.now().millisecondsSinceEpoch;
final answr = makeHammings().skip(999999).first;
final elpsd = DateTime.now().millisecondsSinceEpoch - strt;
print("The ${numhams}th Hamming number is: $answr");
print("in full as: ${trival2BigInt(answr)}");
print("This test took $elpsd milliseconds.");
}
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#FreeBASIC
|
FreeBASIC
|
' FB 1.05.0 Win64
Randomize
Dim n As Integer = Int(Rnd * 10) + 1
Dim guess As Integer
Print "Guess which number I've chosen in the range 1 to 10"
Print
Do
Input " Your guess : "; guess
If n = guess Then
Print "Well guessed!"
End
End If
Loop
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Frink
|
Frink
|
// Guess a Number
target = random[1,10] // Min and max are both inclusive for the random function
guess = 0
println["Welcome to guess a number! I've picked a number between 1 and 10. Try to guess it!"]
while guess != target
{
guessStr = input["What is your guess?"]
guess = parseInt[guessStr]
if guess == undef
println["$guessStr is not a valid guess. Please enter a number from 1 to 10."]
else
guess == target ? println["$guess is correct. Well guessed!"] : println["$guess is not correct. Guess again!"]
}
|
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.
|
#F.23
|
F#
|
let maxsubseq s =
let (_, _, maxsum, maxseq) =
List.fold (fun (sum, seq, maxsum, maxseq) x ->
let (sum, seq) = (sum + x, x :: seq)
if sum < 0 then (0, [], maxsum, maxseq)
else if sum > maxsum then (sum, seq, sum, seq)
else (sum, seq, maxsum, maxseq))
(0, [], 0, []) s
List.rev maxseq
printfn "%A" (maxsubseq [-1 ; -2 ; 3 ; 5 ; 6 ; -2 ; -1 ; 4; -4 ; 2 ; -1])
|
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)
|
#Delphi
|
Delphi
|
program GuessTheNumber;
{$APPTYPE CONSOLE}
uses
SysUtils,
Math;
const
// Set min/max limits
min: Integer = 1;
max: Integer = 10;
var
last,
val,
inp: Integer;
s: string;
// Initialise new game
procedure NewGame;
begin
// Make sure this number isn't the same as the last one
repeat
val := RandomRange(min,max);
until
val <> last;
// Save this number
last := val;
Writeln('Guess a number between ', min, ' and ', max, ' [Answer = ', val, ']');
end;
begin
// Initialise the random number generator with a random value
Randomize;
// Initialise last number
last := 0;
// Initialise user input
s := '';
// Start game
NewGame;
// Loop
repeat
// User input
Readln(s);
// Validate - checxk if input is a number
if TryStrToInt(s,inp) then
begin
// Is it the right number?
if (inp = val) then
begin
// Yes - request a new game
Writeln('Correct! Another go? Y/N');
Readln(s);
if SameText(s,'Y') then
// Start new game
NewGame
else
Exit;
end
else
// Input too low/high
if (inp < val) then
Writeln('Too low! Try again...')
else
if (inp > val) then
Writeln('Too high! Try again...');
end
else
// Input invalid
if not SameText(s,'bored') then
Writeln('Invalid input! Try again...');
until
SameText(s,'bored');
end.
|
http://rosettacode.org/wiki/Greyscale_bars/Display
|
Greyscale bars/Display
|
The task is to display a series of vertical greyscale bars (contrast bars) with a sufficient number of bars to span the entire width of the display.
For the top quarter of the display, the left hand bar should be black, and we then incrementally step through six shades of grey until we have a white bar on the right hand side of the display. (This gives a total of 8 bars)
For the second quarter down, we start with white and step down through 14 shades of gray, getting darker until we have black on the right hand side of the display. (This gives a total of 16 bars).
Halfway down the display, we start with black, and produce 32 bars, ending in white, and for the last quarter, we start with white and step through 62 shades of grey, before finally arriving at black in the bottom right hand corner, producing a total of 64 bars for the bottom quarter.
|
#Wren
|
Wren
|
import "graphics" for Canvas, Color
import "dome" for Window
import "math" for Math
class GreyBars {
construct new(width, height) {
Window.title = "Grey bars example"
Window.resize(width, height)
Canvas.resize(width, height)
_w = width
_h = height
}
init() {
drawBars()
}
drawBars() {
var run = 0
var colorComp = 0 // component of the color
var columnCount = 8
while (columnCount < 128) {
var colorGap = 255 / (columnCount - 1) // by this gap we change the background color
var columnWidth = (_w / columnCount).floor
var columnHeight = (_h / 4).floor
if (run % 2 == 0) { // switches color directions with each iteration of while loop
colorComp = 0
} else {
colorComp = 255
colorGap = -colorGap
}
var ystart = columnHeight * run
var xstart = 0
for (i in 0...columnCount) {
var iColor = Math.round(colorComp)
var nextColor = Color.rgb(iColor, iColor, iColor)
Canvas.rectfill(xstart, ystart, xstart + columnWidth, ystart + columnHeight, nextColor)
xstart = xstart + columnWidth
colorComp = colorComp + colorGap
}
run = run + 1
columnCount = columnCount * 2
}
}
update() {}
draw(alpha) {}
}
var Game = GreyBars.new(640, 320)
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
|
Guess the number/With feedback (player)
|
Task
Write a player for the game that follows the following rules:
The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the scorer scores, in turn, until the computer correctly guesses the target number.
The computer should guess intelligently based on the accumulated scores given. One way is to use a Binary search based algorithm.
Related tasks
Guess the number/With Feedback
Bulls and cows/Player
|
#PicoLisp
|
PicoLisp
|
(de guessTheNumber (Min Max)
(prinl "Think of a number between " Min " and " Max ".")
(prinl "On every guess of mine you should state whether my guess was")
(prinl "too high, too low, or equal to your number by typing 'h', 'l', Or '='")
(use Guess
(loop
(NIL (> Max Min)
(prinl "I think somthing is strange here...") )
(prin
"My guess is "
(setq Guess (+ Min (/ (- Max Min) 2)))
",is this correct? " )
(flush)
(NIL
(case (uppc (car (line)))
("H" (setq Max Guess))
("L" (setq Min Guess))
("=" (nil (prinl "I did it!")))
(T (prinl "I do not understand that...")) ) ) ) ) )
|
http://rosettacode.org/wiki/Guess_the_number/With_feedback_(player)
|
Guess the number/With feedback (player)
|
Task
Write a player for the game that follows the following rules:
The scorer will choose a number between set limits. The computer player will print a guess of the target number. The computer asks for a score of whether its guess is higher than, lower than, or equal to the target. The computer guesses, and the scorer scores, in turn, until the computer correctly guesses the target number.
The computer should guess intelligently based on the accumulated scores given. One way is to use a Binary search based algorithm.
Related tasks
Guess the number/With Feedback
Bulls and cows/Player
|
#Prolog
|
Prolog
|
min(1). max(10).
pick_number(Min, Max) :-
min(Min), max(Max),
format('Pick a number between ~d and ~d, and I will guess it...~nReady? (Enter anything when ready):', [Min, Max]),
read(_).
guess_number(Min, Max) :-
Guess is (Min + Max) // 2,
format('I guess ~d...~nAm I correct (c), too low (l), or too high (h)? ', [Guess]),
repeat,
read(Score),
( Score = l -> NewMin is Guess + 1, guess_number(NewMin, Max)
; Score = h -> NewMax is Guess - 1, guess_number(Min, NewMax)
; Score = c -> writeln('I am correct!')
; writeln('Invalid input'),
false
).
play :-
pick_number(Min, Max),
guess_number(Min, Max).
|
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
|
#Erlang
|
Erlang
|
-module(tasks).
-export([main/0]).
-import(lists, [map/2, member/2, sort/1, sum/1]).
is_happy(X, XS) ->
if
X == 1 ->
true;
X < 1 ->
false;
true ->
case member(X, XS) of
true -> false;
false ->
is_happy(sum(map(fun(Z) -> Z*Z end,
[Y - 48 || Y <- integer_to_list(X)])),
[X|XS])
end
end.
main(X, XS) ->
if
length(XS) == 8 ->
io:format("8 Happy Numbers: ~w~n", [sort(XS)]);
true ->
case is_happy(X, []) of
true -> main(X + 1, [X|XS]);
false -> main(X + 1, XS)
end
end.
main() ->
main(0, []).
|
http://rosettacode.org/wiki/Haversine_formula
|
Haversine formula
|
This page uses content from Wikipedia. The original article was at Haversine formula. The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance)
The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes.
It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles".
Task
Implement a great-circle distance function, or use a library function,
to show the great-circle distance between:
Nashville International Airport (BNA) in Nashville, TN, USA, which is:
N 36°7.2', W 86°40.2' (36.12, -86.67) -and-
Los Angeles International Airport (LAX) in Los Angeles, CA, USA, which is:
N 33°56.4', W 118°24.0' (33.94, -118.40)
User Kaimbridge clarified on the Talk page:
-- 6371.0 km is the authalic radius based on/extracted from surface area;
-- 6372.8 km is an approximation of the radius of the average circumference
(i.e., the average great-elliptic or great-circle radius), where the
boundaries are the meridian (6367.45 km) and the equator (6378.14 km).
Using either of these values results, of course, in differing distances:
6371.0 km -> 2886.44444283798329974715782394574671655 km;
6372.8 km -> 2887.25995060711033944886005029688505340 km;
(results extended for accuracy check: Given that the radii are only
approximations anyways, .01' ≈ 1.0621333 km and .001" ≈ .00177 km,
practical precision required is certainly no greater than about
.0000001——i.e., .1 mm!)
As distances are segments of great circles/circumferences, it is
recommended that the latter value (r = 6372.8 km) be used (which
most of the given solutions have already adopted, anyways).
Most of the examples below adopted Kaimbridge's recommended value of
6372.8 km for the earth radius. However, the derivation of this
ellipsoidal quadratic mean radius
is wrong (the averaging over azimuth is biased). When applying these
examples in real applications, it is better to use the
mean earth radius,
6371 km. This value is recommended by the International Union of
Geodesy and Geophysics and it minimizes the RMS relative error between the
great circle and geodesic distance.
|
#Perl
|
Perl
|
use ntheory qw/Pi/;
sub asin { my $x = shift; atan2($x, sqrt(1-$x*$x)); }
sub surfacedist {
my($lat1, $lon1, $lat2, $lon2) = @_;
my $radius = 6372.8;
my $radians = Pi() / 180;;
my $dlat = ($lat2 - $lat1) * $radians;
my $dlon = ($lon2 - $lon1) * $radians;
$lat1 *= $radians;
$lat2 *= $radians;
my $a = sin($dlat/2)**2 + cos($lat1) * cos($lat2) * sin($dlon/2)**2;
my $c = 2 * asin(sqrt($a));
return $radius * $c;
}
my @BNA = (36.12, -86.67);
my @LAX = (33.94, -118.4);
printf "Distance: %.3f km\n", surfacedist(@BNA, @LAX);
|
http://rosettacode.org/wiki/Hello_world/Text
|
Hello world/Text
|
Hello world/Text is part of Short Circuit's Console Program Basics selection.
Task
Display the string Hello world! on a text console.
Related tasks
Hello world/Graphical
Hello world/Line Printer
Hello world/Newbie
Hello world/Newline omission
Hello world/Standard error
Hello world/Web server
|
#GlovePIE
|
GlovePIE
|
debug="Hello world!"
|
http://rosettacode.org/wiki/Harshad_or_Niven_series
|
Harshad or Niven series
|
The Harshad or Niven numbers are positive integers ≥ 1 that are divisible by the sum of their digits.
For example, 42 is a Harshad number as 42 is divisible by (4 + 2) without remainder.
Assume that the series is defined as the numbers in increasing order.
Task
The task is to create a function/method/procedure to generate successive members of the Harshad sequence.
Use it to:
list the first 20 members of the sequence, and
list the first Harshad number greater than 1000.
Show your output here.
Related task
Increasing gaps between consecutive Niven numbers
See also
OEIS: A005349
|
#PL.2FM
|
PL/M
|
100H:
/* FIND THE SUM OF THE DIGITS OF A 16-BIT NUMBER */
DIGIT$SUM: PROCEDURE(N) BYTE;
DECLARE N ADDRESS, SUM BYTE;
SUM = 0;
DO WHILE N > 0;
SUM = SUM + (N MOD 10);
N = N / 10;
END;
RETURN SUM;
END DIGIT$SUM;
/* FIND THE NEXT HARSHAD NUMBER ABOVE N */
NEXT$HARSHAD: PROCEDURE(N) ADDRESS;
DECLARE N ADDRESS;
NEXT:
N = N + 1;
IF N MOD DIGIT$SUM(N) = 0 THEN
RETURN N;
ELSE
GO TO NEXT;
END NEXT$HARSHAD;
/* CP/M SYSCALL */
BDOS: PROCEDURE(FUNC, ARG);
DECLARE FUNC BYTE, ARG ADDRESS;
GO TO 5;
END BDOS;
/* PRINT A STRING */
PRINT$STRING: PROCEDURE(STRING);
DECLARE STRING ADDRESS;
CALL BDOS(9, STRING);
END PRINT$STRING;
/* PRINT A NUMBER */
PRINT$NUMBER: PROCEDURE(N);
DECLARE S (7) BYTE INITIAL ('..... $');
DECLARE (N, P) ADDRESS, (C BASED P) BYTE;
P = .S(5);
DIGIT:
P = P - 1;
C = (N MOD 10) + '0';
N = N / 10;
IF N > 0 THEN GO TO DIGIT;
CALL PRINT$STRING(P);
END PRINT$NUMBER;
DECLARE CRLF DATA (13,10,'$');
DECLARE N ADDRESS INITIAL (0), S BYTE;
/* PRINT FIRST 20 HARSHADS */
CALL PRINT$STRING(.'FIRST 20: $');
DO S = 1 TO 20;
CALL PRINT$NUMBER(N := NEXT$HARSHAD(N));
END;
CALL PRINT$STRING(.CRLF);
/* PRINT HARSHAD NUMBER ABOVE 1000 */
CALL PRINT$STRING(.'FIRST ABOVE 1000: $');
CALL PRINT$NUMBER(NEXT$HARSHAD(1000));
CALL PRINT$STRING(.CRLF);
CALL BDOS(0,0);
EOF
|
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
|
#Liberty_BASIC
|
Liberty BASIC
|
NOTICE "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
|
#Lingo
|
Lingo
|
_player.alert("Goodbye, World!")
|
http://rosettacode.org/wiki/GUI_component_interaction
|
GUI component interaction
|
Almost every application needs to communicate with the user in some way.
Therefore, a substantial part of the code deals with the interaction
of program logic with GUI components.
Typically, the following is needed:
put values into input fields under program control
read and check input from the user
pop up dialogs to query the user for further information
Task
For a minimal "application", write a program that presents a form with three components to the user:
a numeric input field ("Value")
a button ("increment")
a button ("random")
The field is initialized to zero.
The user may manually enter a new value into the field,
or increment its value with the "increment" button.
Entering a non-numeric value should be either impossible,
or issue an error message.
Pressing the "random" button presents a confirmation dialog,
and resets the field's value to a random value if the answer is "Yes".
(This task may be regarded as an extension of the task Simple windowed application).
|
#Vala
|
Vala
|
bool validate_input(Gtk.Window window, string str){
int64 val;
bool ret = int64.try_parse(str,out val);;
if(!ret){
var dialog = new Gtk.MessageDialog(window,
Gtk.DialogFlags.MODAL,
Gtk.MessageType.ERROR,
Gtk.ButtonsType.OK,
"Invalid value");
dialog.run();
dialog.destroy();
}
return ret;
}
int main (string[] args) {
Gtk.init (ref args);
var window = new Gtk.Window();
window.title = "Rosetta Code";
window.window_position = Gtk.WindowPosition.CENTER;
window.destroy.connect(Gtk.main_quit);
window.set_default_size(0,0);
var box = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 1);
box.set_border_width(1);
var label = new Gtk.Label ("Value:");
var entry = new Gtk.Entry();
entry.set_text("0"); //initialize to zero
entry.activate.connect (() => {
// read and validate the entered value
validate_input(window, entry.get_text());
});
// button to increment
var ib = new Gtk.Button.with_label("increment");
ib.clicked.connect(() => {
// read and validate the entered value
var str = entry.get_text();
if(validate_input(window, str)){
entry.set_text((int.parse(str)+1).to_string());
}
});
// button to put in a random value if confirmed
var rb = new Gtk.Button.with_label("random");
rb.clicked.connect (() => {
var dialog = new Gtk.MessageDialog(window,
Gtk.DialogFlags.MODAL,
Gtk.MessageType.QUESTION,
Gtk.ButtonsType.YES_NO,
"set random value");
var answer = dialog.run();
dialog.destroy();
if(answer == Gtk.ResponseType.YES){
entry.set_text(Random.int_range(0,10000).to_string());
}
});
box.pack_start(label, false, false, 2);
box.pack_start(entry, false, false, 2);
box.pack_start(ib, false, false, 2);
box.pack_start(rb, false, false, 2);
window.add(box);
window.show_all();
Gtk.main ();
return 0;
}
|
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.
|
#C.2B.2B
|
C++
|
#include <bitset>
#include <iostream>
#include <string>
#include <assert.h>
uint32_t gray_encode(uint32_t b)
{
return b ^ (b >> 1);
}
uint32_t gray_decode(uint32_t g)
{
for (uint32_t bit = 1U << 31; bit > 1; bit >>= 1)
{
if (g & bit) g ^= bit >> 1;
}
return g;
}
std::string to_binary(int value) // utility function
{
const std::bitset<32> bs(value);
const std::string str(bs.to_string());
const size_t pos(str.find('1'));
return pos == std::string::npos ? "0" : str.substr(pos);
}
int main()
{
std::cout << "Number\tBinary\tGray\tDecoded\n";
for (uint32_t n = 0; n < 32; ++n)
{
uint32_t g = gray_encode(n);
assert(gray_decode(g) == n);
std::cout << n << "\t" << to_binary(n) << "\t" << to_binary(g) << "\t" << g << "\n";
}
}
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#Clojure
|
Clojure
|
(use '[clojure.java.shell :only [sh]])
(sh "echo" "Hello")
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#Common_Lisp
|
Common Lisp
|
(trivial-shell:shell-command "uname -imp")
|
http://rosettacode.org/wiki/Get_system_command_output
|
Get system command output
|
Task
Execute a system command and get its output into the program. The output may be stored in any kind of collection (array, list, etc.).
Related task
Execute a system command
|
#D
|
D
|
import std.process;
import std.stdio;
void main() {
auto cmd = executeShell("echo hello");
if (cmd.status == 0) {
writeln("Output: ", cmd.output);
} else {
writeln("Failed to execute command, status=", cmd.status);
}
}
|
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!
|
#68000_Assembly
|
68000 Assembly
|
EXG D0,D1 ;swap the contents of D0 and D1
EXG A0,A1 ;swap the contents of A0 and A1
|
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.
|
#Applesoft_BASIC
|
Applesoft BASIC
|
100 REMMAX
110 R$ = "":E$ = ""
120 L = LEN (L$)
130 IF L = 0 THEN RETURN
140 FOR I = 1 TO L
150 C$ = MID$ (L$,I,1)
160 SP = C$ = " "
170 IF SP THEN GOSUB 200
180 E$ = E$ + C$
190 NEXT I
200 C$ = ""
210 IF E$ = "" THEN RETURN
220 V = VAL (E$):V$ = R$
230 E$ = "":E = V$ = ""
240 IF E AND V = 0 THEN RETURN
250 R$ = STR$ (V)
260 IF E THEN RETURN
270 R = VAL (V$)
280 IF R < V THEN RETURN
290 R$ = V$: RETURN
|
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