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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
|
#MAXScript
|
MAXScript
|
rand = random 1 10
clearListener()
while true do
(
userval = getKBValue prompt:"Enter an integer between 1 and 10: "
if userval == rand do (format "\nWell guessed!\n"; exit)
format "\nChoose another value\n"
)
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#Mercury
|
Mercury
|
:- module guess.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module random, string.
main(!IO) :-
time(Time, !IO),
random.init(Time, Rand),
random.random(1, 10, N, Rand, _),
main(from_int(N) ++ "\n", !IO).
:- pred main(string::in, io::di, io::uo) is det.
main(N, !IO) :-
io.write_string("Guess the number: ", !IO),
io.read_line_as_string(Res, !IO),
(
Res = ok(S),
( if S = N then io.write_string("Well guessed!\n", !IO)
else main(N, !IO) )
;
Res = error(E)
;
Res = eof
).
:- pred time(int::out, io::di, io::uo) is det.
:- pragma foreign_decl("C", "#include <time.h>").
:- pragma foreign_proc("C", time(Int::out, _IO0::di, _IO1::uo),
[will_not_call_mercury, promise_pure],
"Int = time(NULL);").
|
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.
|
#Mathprog
|
Mathprog
|
/*Special ordered set of type N
Nigel_Galloway
January 26th, 2012
*/
param Lmax;
param Lmin;
set SOS;
param Sx{SOS};
var db{Lmin..Lmax,SOS}, binary;
maximize s : sum{q in (Lmin..Lmax),t in (0..q-1), z in SOS: z > (q-1)} Sx[z-t]*db[q,z];
sos1 : sum{t in (Lmin..Lmax),z in SOS: z > (t-1)} db[t,z] = 1;
solve;
for{t in (Lmin..Lmax),z in SOS: db[t,z] == 1} {
printf "\nA sub-sequence of length %d sums to %f:\n", t,s;
printf{q in (z-t+1)..z} " %f", Sx[q];
}
printf "\n\n";
data;
param Lmin := 1;
param Lmax := 6;
param:
SOS: Sx :=
1 7
2 4
3 -11
4 6
5 3
6 1
;
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.
|
#MATLAB_.2F_Octave
|
MATLAB / Octave
|
function [S,GS]=gss(a)
% Greatest subsequential sum
a =[0;a(:);0]';
ix1 = find(a(2:end) >0 & a(1:end-1) <= 0);
ix2 = find(a(2:end)<=0 & a(1:end-1) > 0);
K = 0;
S = 0;
for k = 1:length(ix1)
s = sum(a(ix1(k)+1:ix2(k)));
if (s>S)
S=s; K=k;
end;
end;
GS = a(ix1(K)+1:ix2(K));
|
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)
|
#Frink
|
Frink
|
// Guess a Number with feedback.
target = random[1,100] // 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 100. 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 100."]
next
}
if guess < target
println["My number is higher than $guess."]
if guess > target
println["My number is lower than $guess."]
if guess == target
println["$guess is correct! Well guessed!"]
}
|
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
|
#ZX_Spectrum_Basic
|
ZX Spectrum Basic
|
10 LET min=1: LET max=100
20 PRINT "Think of a number between ";min;" and ";max
30 PRINT "I will try to guess your number."
40 LET guess=INT ((min+max)/2)
50 PRINT "My guess is ";guess
60 INPUT "Is it higuer than, lower than or equal to your number? ";a$
65 LET a$=a$(1)
70 IF a$="L" OR a$="l" THEN LET min=guess+1: GO TO 40
80 IF a$="H" OR a$="h" THEN LET max=guess-1: GO TO 40
90 IF a$="E" OR a$="e" THEN PRINT "Goodbye.": STOP
100 PRINT "Sorry, I didn't understand your answer.": GO TO 60
|
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
|
#Haskell
|
Haskell
|
import Data.Char (digitToInt)
import Data.Set (member, insert, empty)
isHappy :: Integer -> Bool
isHappy = p empty
where
p _ 1 = True
p s n
| n `member` s = False
| otherwise = p (insert n s) (f n)
f = sum . fmap ((^ 2) . toInteger . digitToInt) . show
main :: IO ()
main = mapM_ print $ take 8 $ filter isHappy [1 ..]
|
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.
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
include "float.s7i";
include "math.s7i";
const func float: greatCircleDistance (in float: latitude1, in float: longitude1,
in float: latitude2, in float: longitude2) is func
result
var float: distance is 0.0;
local
const float: EarthRadius is 6372.8; # Average great-elliptic or great-circle radius in kilometers
begin
distance := 2.0 * EarthRadius * asin(sqrt(sin(0.5 * (latitude2 - latitude1)) ** 2 +
cos(latitude1) * cos(latitude2) *
sin(0.5 * (longitude2 - longitude1)) ** 2));
end func;
const func float: degToRad (in float: degrees) is
return degrees * 0.017453292519943295769236907684886127;
const proc: main is func
begin
writeln("Distance in kilometers between BNA and LAX");
writeln(greatCircleDistance(degToRad(36.12), degToRad(-86.67), # Nashville International Airport (BNA)
degToRad(33.94), degToRad(-118.4)) # Los Angeles International Airport (LAX)
digits 2);
end func;
|
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.
|
#Sidef
|
Sidef
|
class EarthPoint(lat, lon) {
const earth_radius = 6371 # mean earth radius
const radian_ratio = Num.pi/180
# accessors for radians
method latR { self.lat * radian_ratio }
method lonR { self.lon * radian_ratio }
method haversine_dist(EarthPoint p) {
var arc = EarthPoint(
self.lat - p.lat,
self.lon - p.lon,
)
var a = Math.sum(
(arc.latR / 2).sin**2,
(arc.lonR / 2).sin**2 *
self.latR.cos * p.latR.cos
)
earth_radius * a.sqrt.asin * 2
}
}
var BNA = EarthPoint.new(lat: 36.12, lon: -86.67)
var LAX = EarthPoint.new(lat: 33.94, lon: -118.4)
say BNA.haversine_dist(LAX) #=> 2886.444442837983299747157823945746716...
|
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
|
#HLA
|
HLA
|
program goodbyeWorld;
#include("stdlib.hhf")
begin goodbyeWorld;
stdout.put( "Hello world!" nl );
end goodbyeWorld;
|
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
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
const func integer: sumOfDigits (in var integer: num) is func
result
var integer: sum is 0;
begin
repeat
sum +:= num rem 10;
num := num div 10;
until num = 0;
end func;
const func integer: nextHarshadNum (inout integer: num) is func
result
var integer: harshadNumber is 0;
begin
while num mod sumOfDigits(num) <> 0 do
incr(num);
end while;
harshadNumber := num;
end func;
const proc: main is func
local
var integer: current is 1;
var integer: count is 0;
begin
for count range 1 to 20 do
write(nextHarshadNum(current) <& " ");
incr(current);
end for;
current := 1001;
writeln(" ... " <& nextHarshadNum(current));
end func;
|
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
|
#OxygenBasic
|
OxygenBasic
|
print "Hello World!"
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Oxygene
|
Oxygene
|
<?xml version="1.0" standalone="no"?> <!--*- mode: xml -*-->
<!DOCTYPE glade-interface SYSTEM "http://glade.gnome.org/glade-2.24.dtd">
<glade-interface>
<widget class="GtkWindow" id="hworld">
<property name="visible">True</property>
<property name="title">Hello World</property>
<property name="modal">False</property>
<property name="resizable">True</property>
<property name="default_width">200</property>
<property name="default_height">100</property>
<signal name="delete_event" handler="on_hworld_delete_event"/>
<child>
<widget class="GtkLabel" id="label1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">Farewell, cruel world.</property>
</widget>
</child>
</widget>
</glade-interface>
|
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.
|
#JavaScript
|
JavaScript
|
export function encode (number) {
return number ^ (number >> 1)
}
export function decode (encodedNumber) {
let number = encodedNumber
while (encodedNumber >>= 1) {
number ^= encodedNumber
}
return number
}
|
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.
|
#Julia
|
Julia
|
grayencode(n::Integer) = n ⊻ (n >> 1)
function graydecode(n::Integer)
r = n
while (n >>= 1) != 0
r ⊻= n
end
return r
end
|
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
|
#Ursa
|
Ursa
|
> decl iodevice iod
> decl string<> arg
> append "ifconfig" arg
> set iod (ursa.util.process.start arg)
> decl string<> output
> set output (iod.readlines)
> for (decl int i) (< i (size output)) (inc i)
.. out output<i> endl console
..end for
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
options=3<RXCSUM,TXCSUM>
inet6 ::1 prefixlen 128
inet 127.0.0.1 netmask 0xff000000
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
nd6 options=1<PERFORMNUD>
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=27<RXCSUM,TXCSUM,VLAN_MTU,TSO4>
ether d4:9a:20:b8:8d:2c
nd6 options=1<PERFORMNUD>
media: autoselect
status: inactive
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:26:08:e0:67:cc
inet6 fe80::226:8ff:fee0:67cc%en1 prefixlen 64 scopeid 0x5
inet 172.20.30.66 netmask 0xffffff00 broadcast 172.20.30.255
nd6 options=1<PERFORMNUD>
media: autoselect
status: active
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078
lladdr d4:9a:20:ff:fe:b8:8d:2c
nd6 options=1<PERFORMNUD>
media: autoselect <full-duplex>
status: inactive
p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304
ether 02:26:08:e0:67:cc
media: autoselect
status: inactive
>
|
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
|
#VBScript
|
VBScript
|
For Each line In ExecCmd("ipconfig /all")
Wscript.Echo line
Next
'Execute the given command and return the output in a text array.
Function ExecCmd(cmd)
'Execute the command
Dim wso : Set wso = CreateObject("Wscript.Shell")
Dim exec : Set exec = wso.Exec(cmd)
Dim res : res = ""
'Read all result text from standard output
Do
res = res & VbLf & exec.StdOut.ReadLine
Loop Until exec.StdOut.AtEndOfStream
'Return as a text array
ExecCmd = Split(Mid(res,2),vbLf)
End Function
|
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
|
#Visual_Basic_.NET
|
Visual Basic .NET
|
Module Module1
Sub Main()
Dim proccess As New Process
Dim startInfo As New ProcessStartInfo
startInfo.WindowStyle = ProcessWindowStyle.Hidden
startInfo.FileName = "cmd.exe"
startInfo.Arguments = "/c echo Hello World"
startInfo.RedirectStandardOutput = True
startInfo.UseShellExecute = False
proccess.StartInfo = startInfo
proccess.Start()
Dim output = proccess.StandardOutput.ReadToEnd
Console.WriteLine("Output is {0}", output)
End Sub
End Module
|
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!
|
#Applesoft_BASIC
|
Applesoft BASIC
|
A=43:B=47:H=A:A=B:B=H:?" A="A" B="B;
|
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.
|
#Burlesque
|
Burlesque
|
blsq ) {88 99 77 66 55}>]
99
|
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.
|
#AutoIt
|
AutoIt
|
_GCD(18, 12)
_GCD(1071, 1029)
_GCD(3528, 3780)
Func _GCD($ia, $ib)
Local $ret = "GCD of " & $ia & " : " & $ib & " = "
Local $imod
While True
$imod = Mod($ia, $ib)
If $imod = 0 Then Return ConsoleWrite($ret & $ib & @CRLF)
$ia = $ib
$ib = $imod
WEnd
EndFunc ;==>_GCD
|
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.
|
#Red
|
Red
|
>> f: request-file
>> str: read f
>> replace/all str "Goodbye London!" "Hello New York!"
>> write f str
|
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.
|
#REXX
|
REXX
|
/*REXX program reads the files specified and globally replaces a string. */
old= "Goodbye London!" /*the old text to be replaced. */
new= "Hello New York!" /* " new " used for replacement. */
parse arg fileList /*obtain required list of files from CL*/
#= words(fileList) /*the number of files in the file list.*/
do f=1 for #; fn= translate( word(fileList, f), , ','); say; say
say '──────── file is being read: ' fn " ("f 'out of' # "files)."
call linein fn,1,0 /*position the file for input. */
changes= 0 /*the number of changes in file so far.*/
do rec=0 while lines(fn)\==0 /*read a file (if it exists). */
@.rec= linein(fn) /*read a record (line) from the file. */
if pos(old, @.rec)==0 then iterate /*Anything to change? No, then skip. */
changes= changes + 1 /*flag that file contents have changed.*/
@.rec= changestr(old, @.rec, new) /*change the @.rec record, old ──► new.*/
end /*rec*/
say '──────── file has been read: ' fn", with " rec 'records.'
if changes==0 then do; say '──────── file not changed: ' fn; iterate; end
call lineout fn,,1 /*position file for output at 1st line.*/
say '──────── file being changed: ' fn
do r=0 for rec; call lineout fn, @.r /*re─write the contents of the file. */
end /*r*/
say '──────── file was changed: ' fn " with" changes 'lines changed.'
end /*f*/ /*stick a fork in it, we're all done. */
|
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).
|
#Burlesque
|
Burlesque
|
blsq ) 27{^^^^2.%{3.*1.+}\/{2./}\/ie}{1!=}w!bx{\/+]}{\/isn!}w!L[
112
|
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.
|
#Wren
|
Wren
|
import "graphics" for Canvas, Color, ImageData
import "dome" for Window
class PercentageDifference {
construct new(width, height, image1, image2) {
Window.title = "Grayscale Image"
Window.resize(width, height)
Canvas.resize(width, height)
_image1 = image1
_image2 = image2
_img1 = ImageData.loadFromFile(image1)
_img2 = ImageData.create(image2, _img1.width, _img1.height)
}
init() {
toGrayScale()
// display images side by side
_img1.draw(0, 0)
_img2.draw(550, 0)
Canvas.print(_image1, 200, 525, Color.white)
Canvas.print(_image2, 750, 525, Color.white)
}
toGrayScale() {
for (x in 0..._img1.width) {
for (y in 0..._img1.height) {
var c1 = _img1.pget(x, y)
var lumin = (0.2126 * c1.r + 0.7152 * c1.g + 0.0722 * c1.b).floor
var c2 = Color.rgb(lumin, lumin,lumin, c1.a)
_img2.pset(x, y, c2)
}
}
}
update() {}
draw(alpha) {}
}
var Game = PercentageDifference.new(1100, 550, "Lenna100.jpg", "Lenna-grayscale.jpg")
|
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).
|
#Haskell
|
Haskell
|
hamming = 1 : map (2*) hamming `union` map (3*) hamming `union` map (5*) hamming
union a@(x:xs) b@(y:ys) = case compare x y of
LT -> x : union xs b
EQ -> x : union xs ys
GT -> y : union a ys
main = do
print $ take 20 hamming
print (hamming !! (1691-1), hamming !! (1692-1))
print $ hamming !! (1000000-1)
-- Output:
-- [1,2,3,4,5,6,8,9,10,12,15,16,18,20,24,25,27,30,32,36]
-- (2125764000,2147483648)
-- 519312780448388736089589843750000000000000000000000000000000000000000000000000000000
|
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
|
#min
|
min
|
randomize
9 random succ
"Guess my number between 1 and 10." puts!
("Your guess" ask int over ==) 'pop ("Wrong." puts!) () linrec
"Well guessed!" puts!
|
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
|
#MiniScript
|
MiniScript
|
num = ceil(rnd*10)
while true
x = val(input("Your guess?"))
if x == num then
print "Well guessed!"
break
end if
end while
|
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.
|
#NetRexx
|
NetRexx
|
/* REXX ***************************************************************
* 10.08.2012 Walter Pachl Pascal algorithm -> Rexx -> NetRexx
**********************************************************************/
s=' -1 -2 3 5 6 -2 -1 4 -4 2 -1'
maxSum = 0
seqStart = 0
seqEnd = -1
Loop i = 1 To s.words()
seqSum = 0
Loop j = i to s.words()
seqSum = seqSum + s.word(j)
if seqSum > maxSum then Do
maxSum = seqSum
seqStart = i
seqEnd = j
end
end
end
Say 'Sequence:'
Say s
Say 'Subsequence with greatest sum: '
If seqend<seqstart Then
Say 'empty'
Else Do
ol=' '.copies(seqStart-1)
Loop i = seqStart to seqEnd
w=s.word(i)
ol=ol||w.right(3)
End
Say ol
Say 'Sum:' maxSum
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.
|
#Nim
|
Nim
|
proc maxsum(s: openArray[int]): int =
var maxendinghere = 0
for x in s:
maxendinghere = max(maxendinghere + x, 0)
result = max(result, maxendinghere)
echo maxsum(@[-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)
|
#Genie
|
Genie
|
[indent=4]
/*
Number guessing with feedback, in Genie
from https://wiki.gnome.org/Projects/Genie/AdvancedSample
valac numberGuessing.gs
./numberGuessing
*/
class NumberGuessing
prop min:int
prop max:int
construct(m:int, n:int)
self.min = m
self.max = n
def start()
try_count:int = 0
number:int = Random.int_range(min, max)
stdout.printf("Welcome to Number Guessing!\n\n")
stdout.printf("I have thought up a number between %d and %d\n", min, max)
stdout.printf("which you have to guess. I will give hints as we go.\n\n")
while true
stdout.printf("Try #%d, ", ++try_count)
stdout.printf("please enter a number between %d and %d: ", min, max)
line:string? = stdin.read_line()
if line is null
stdout.printf("bailing...\n")
break
input:int64 = 0
unparsed:string = ""
converted:bool = int64.try_parse(line, out input, out unparsed)
if not converted or line is unparsed
stdout.printf("Sorry, input seems invalid\n")
continue
guess:int = (int)input
if number is guess
stdout.printf("Congratulations! You win.\n")
break
else
stdout.printf("Try again. The number in mind is %s than %d.\n",
number > guess ? "greater" : "less", guess)
init
var game = new NumberGuessing(1, 100)
game.start()
|
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
|
#Icon_and_Unicon
|
Icon and Unicon
|
procedure main(arglist)
local n
n := arglist[1] | 8 # limiting number of happy numbers to generate, default=8
writes("The first ",n," happy numbers are:")
every writes(" ", happy(seq()) \ n )
write()
end
procedure happy(i) #: returns i if i is happy
local n
if 4 ~= (0 <= i) then { # unhappy if negative, 0, or 4
if i = 1 then return i
every (n := 0) +:= !i ^ 2
if happy(n) then return i
}
end
|
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.
|
#smart_BASIC
|
smart BASIC
|
'*** LAT/LONG for Nashville International Airport (BNA)
lat1=36.12
Lon1=-86.67
'*** LAT/LONG for Los Angeles International Airport (LAX)
Lat2=33.94
Lon2=-118.40
'*** Units: K=kilometers M=miles N=nautical miles
Unit$ = "K"
Result=HAVERSINE(Lat1,Lon1,Lat2,Lon2,Unit$)
R$=STR$(Result,"#,###.##")
PRINT "The distance between Nashville International Airport and Los Angeles International Airport in kilometers is: "&R$
STOP
DEF HAVERSINE(Lat1,Lon1,Lat2,Lon2,Unit$)
'---------------------------------------------------------------
'*** Haversine Formula - Calculate distances by LAT/LONG
'
'*** Pass to it the LAT/LONG of the two locations, and then unit of measure
'*** Usage: X=HAVERSINE(Lat1,Lon1,Lat2,Lon2,Unit$)
PI=3.14159265358979323846
Radius=6372.8
Lat1=(Lat1*PI/180)
Lon1=(Lon1*PI/180)
Lat2=(Lat2*PI/180)
Lon2=(Lon2*PI/180)
DLon=Lon1-Lon2
Answer=ACOS(SIN(Lat1)*SIN(Lat2)+COS(Lat1)*COS(Lat2)*COS(DLon))*Radius
IF UNIT$="M" THEN Answer=Answer*0.621371192
IF UNIT$="N" THEN Answer=Answer*0.539956803
RETURN Answer
ENDDEF
|
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.
|
#Stata
|
Stata
|
program spheredist
version 15.0
syntax varlist(min=4 max=4 numeric), GENerate(namelist max=1) ///
[Radius(real 6371) ALTitude(real 0) LABel(string)]
confirm new variable `generate'
local lat1 : word 1 of `varlist'
local lon1 : word 2 of `varlist'
local lat2 : word 3 of `varlist'
local lon2 : word 4 of `varlist'
local r=2*(`radius'+`altitude'/1000)
local k=_pi/180
gen `generate'=`r'*asin(sqrt(sin((`lat2'-`lat1')*`k'/2)^2+ ///
cos(`lat1'*`k')*cos(`lat2'*`k')*sin((`lon2'-`lon1')*`k'/2)^2))
if `"`label'"' != "" {
label variable `generate' `"`label'"'
}
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
|
#HolyC
|
HolyC
|
"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
|
#Sidef
|
Sidef
|
func harshad() {
var n = 0;
{
++n while !(n %% n.digits.sum);
n;
}
}
var iter = harshad();
say 20.of { iter.run };
var n;
do {
n = iter.run
} while (n <= 1000);
say n;
|
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
|
#Oz
|
Oz
|
declare
[QTk] = {Module.link ['x-oz://system/wp/QTk.ozf']}
Window = {QTk.build td(label(text:"Goodbye, World!"))}
in
{Window show}
|
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
|
#Panoramic
|
Panoramic
|
print "Goodbye, World!"
'Prints in the upper left corner of the window.
|
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.
|
#K
|
K
|
xor: {~x=y}
gray:{x[0],xor':x}
/ variant: using shift
gray1:{(x[0],xor[1_ x;-1_ x])}
/ variant: iterative
gray2:{x[0],{:[x[y-1]=1;~x[y];x[y]]}[x]'1+!(#x)-1}
|
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.
|
#Kotlin
|
Kotlin
|
// version 1.0.6
object Gray {
fun encode(n: Int) = n xor (n shr 1)
fun decode(n: Int): Int {
var p = n
var nn = n
while (nn != 0) {
nn = nn shr 1
p = p xor nn
}
return p
}
}
fun main(args: Array<String>) {
println("Number\tBinary\tGray\tDecoded")
for (i in 0..31) {
print("$i\t${Integer.toBinaryString(i)}\t")
val g = Gray.encode(i)
println("${Integer.toBinaryString(g)}\t${Gray.decode(g)}")
}
}
|
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
|
#Wren
|
Wren
|
/* get_system_command_output.wren */
class Command {
foreign static output(name, param) // the code for this is provided by Go
}
System.print(Command.output("ls", "-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
|
#Yabasic
|
Yabasic
|
// Rosetta Code problem: https://www.rosettacode.org/wiki/Get_system_command_output
// by Jjuanhdez, 06/2022
if peek$("os") = "unix" then
c$ = "ls *"
else //"windows"
c$ = "dir *.*"
fi
open("dir_output.txt") for writing as #1
print #1 system$(c$)
close #1
|
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
|
#zkl
|
zkl
|
zkl: System.cmd("date >foo.txt")
0 // date return code
zkl: File("foo.txt").read().text
Wed Aug 20 00:28:55 PDT 2014
|
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!
|
#Axe
|
Axe
|
Exch(°A,°B,2)
|
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.
|
#C
|
C
|
#include <assert.h>
float max(unsigned int count, float values[]) {
assert(count > 0);
size_t idx;
float themax = values[0];
for(idx = 1; idx < count; ++idx) {
themax = values[idx] > themax ? values[idx] : themax;
}
return themax;
}
|
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.
|
#AWK
|
AWK
|
$ awk 'function gcd(p,q){return(q?gcd(q,(p%q)):p)}{print gcd($1,$2)}'
12 16
4
22 33
11
45 67
1
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#Ring
|
Ring
|
filenames = ["ReadMe.txt", "ReadMe2.txt"]
for fn in filenames
fp = fopen(fn,"r")
str = fread(fp,getFileSize(fp))
str = substr(str, "Greetings", "Hello")
fclose(fp)
fp = fopen(fn,"w")
fwrite(fp, str)
fclose(fp)
next
func getFileSize fp
C_FILESTART = 0
C_FILEEND = 2
fseek(fp,0,C_FILEEND)
nFileSize = ftell(fp)
fseek(fp,0,C_FILESTART)
return nFileSize
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#Ruby
|
Ruby
|
ruby -pi -e "gsub('Goodbye London!', 'Hello New York!')" a.txt b.txt c.txt
|
http://rosettacode.org/wiki/Globally_replace_text_in_several_files
|
Globally replace text in several files
|
Task
Replace every occurring instance of a piece of text in a group of text files with another one.
For this task we want to replace the text "Goodbye London!" with "Hello New York!" for a list of files.
|
#Run_BASIC
|
Run BASIC
|
file$(1) ="data1.txt"
file$(2) ="data2.txt"
file$(3) ="data3.txt"
for i = 1 to 3
open file$(i) for input as #in
fileBefore$ = input$( #in, lof( #in))
close #in
fileAfter$ = strRep$(fileBefore$, "Goodbye London!", "Hello New York!")
open "new_" + file$(i) for output as #out
print #out,fileAfter$;
close #out
next i
end
' --------------------------------
' string replace - rep str with
' --------------------------------
FUNCTION strRep$(str$,rep$,with$)
ln = len(rep$)
ln1 = ln - 1
i = 1
while i <= len(str$)
if mid$(str$,i,ln) = rep$ then
strRep$ = strRep$ + with$
i = i + ln1
else
strRep$ = strRep$ + mid$(str$,i,1)
end if
i = i + 1
WEND
END FUNCTION
|
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.
|
#Rust
|
Rust
|
//! Author: Rahul Sharma
//! Github: <https://github.com/creativcoder>
use std::fs::File;
use std::fs::OpenOptions;
use std::io::BufRead;
use std::io::BufReader;
use std::io::BufWriter;
use std::io::Write;
fn main() {
// opens file for writing replaced lines
let out_fd = OpenOptions::new()
.write(true)
.create(true)
.open("resources/output.txt");
// defining a closure write_line
let write_line = |line: &str| match out_fd {
Ok(ref v) => {
let mut writer = BufWriter::new(v);
writer.write_all(line.as_bytes()).unwrap();
}
Err(ref e) => {
println!("Error:{}", e);
}
};
// read input file
match File::open("resources/paragraph.txt") {
Ok(handle) => {
let mut reader = BufReader::new(handle);
let mut line = String::new();
// read the first line
reader.read_line(&mut line).unwrap();
// loop until line end
while line.trim() != "" {
let mut replaced_line = line.trim().replace("Goodbye London!", "Hello New York!");
replaced_line += "\n";
write_line(&replaced_line[..]);
line.clear();
reader.read_line(&mut line).unwrap();
}
}
Err(e) => println!("Error:{}", e),
}
}
|
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).
|
#C
|
C
|
#include <stdio.h>
#include <stdlib.h>
int hailstone(int n, int *arry)
{
int hs = 1;
while (n!=1) {
hs++;
if (arry) *arry++ = n;
n = (n&1) ? (3*n+1) : (n/2);
}
if (arry) *arry++ = n;
return hs;
}
int main()
{
int j, hmax = 0;
int jatmax, n;
int *arry;
for (j=1; j<100000; j++) {
n = hailstone(j, NULL);
if (hmax < n) {
hmax = n;
jatmax = j;
}
}
n = hailstone(27, NULL);
arry = malloc(n*sizeof(int));
n = hailstone(27, arry);
printf("[ %d, %d, %d, %d, ...., %d, %d, %d, %d] len=%d\n",
arry[0],arry[1],arry[2],arry[3],
arry[n-4], arry[n-3], arry[n-2], arry[n-1], n);
printf("Max %d at j= %d\n", hmax, jatmax);
free(arry);
return 0;
}
|
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.
|
#Yabasic
|
Yabasic
|
import image
open window 600,600
GetImage(1, "House.bmp")
DisplayImage(1, 0, 0)
For x = 1 to 300
For y = 1 to 300
z$ = getbit$(x,y,x,y)
r = dec(mid$(z$,9,2))
g = dec(mid$(z$,11,2))
b = dec(mid$(z$,13,2))
r3=(r+g+b)/3
g3=(r+g+b)/3
b3=(r+g+b)/3
color r3,g3,b3
dot x+300,y+300
next y
next x
|
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.
|
#zkl
|
zkl
|
fcn toGrayScale(img){ // in-place conversion
foreach x,y in (img.w,img.h){
r,g,b:=img[x,y].toBigEndian(3);
lum:=(0.2126*r + 0.7152*g + 0.0722*b).toInt();
img[x,y]=((lum*256) + lum)*256 + lum;
}
}
|
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).
|
#Icon_and_Unicon
|
Icon and Unicon
|
# Lazily generate the three Hamming numbers that can be derived directly
# from a known Hamming number h
class Triplet : Class (cv, ce)
method nextVal()
suspend cv := @ce
end
initially (baseNum)
cv := 2*baseNum
ce := create (3|5)*baseNum
end
# Generate Hamming numbers, in order. Default is first 30
# But an optional argument can be used to generate more (or less)
# e.g. hamming 5000 generates the first 5000.
procedure main(args)
limit := integer(args[1]) | 30
every write("\t", generateHamming() \ limit)
end
# Do the work. Start with known Hamming number 1 and maintain
# a set of triplet Hamming numbers as they get derived from that
# one. Most of the code here is to figure out which Hamming
# number is next in sequence (while removing duplicates)
procedure generateHamming()
triplers := set()
insert(triplers, Triplet(1))
suspend 1
repeat {
# Pick a Hamming triplet that *may* have the next smallest number
t1 := !triplers # any will do to start
every t1 ~=== (t2 := !triplers) do {
if t1.cv > t2.cv then {
# oops we were wrong, switch assumption
t1 := t2
}
else if t1.cv = t2.cv then {
# t2's value is a duplicate, so
# advance triplet t2, if none left in t2, remove it
t2.nextVal() | delete(triplers, t2)
}
}
# Ok, t1 has the next Hamming number, grab it
suspend t1.cv
insert(triplers, Triplet(t1.cv))
# Advance triplet t1, if none left in t1, remove it
t1.nextVal() | delete(triplers, t1)
}
end
|
http://rosettacode.org/wiki/Guess_the_number
|
Guess the number
|
Task
Write a program where the program chooses a number between 1 and 10.
A player is then prompted to enter a guess. If the player guesses wrong, then the prompt appears again until the guess is correct.
When the player has made a successful guess the computer will issue a "Well guessed!" message, and the program exits.
A conditional loop may be used to repeat the guessing until the user is correct.
Related tasks
Bulls and cows
Bulls and cows/Player
Guess the number/With Feedback
Mastermind
|
#MIPS_Assembly
|
MIPS Assembly
|
# WRITTEN: August 26, 2016 (at midnight...)
# This targets MARS implementation and may not work on other implementations
# Specifically, using MARS' random syscall
.data
take_a_guess: .asciiz "Make a guess:"
good_job: .asciiz "Well guessed!"
.text
#retrieve system time as a seed
li $v0,30
syscall
#use the high order time stored in $a1 as the seed arg
move $a1,$a0
#set the seed
li $v0,40
syscall
#generate number 0-9 (random int syscall generates a number where):
# 0 <= $v0 <= $a1
li $a1,10
li $v0,42
syscall
#increment the randomly generated number and store in $v1
add $v1,$a0,1
loop: jal print_take_a_guess
jal read_int
#go back to beginning of loop if user hasn't guessed right,
# else, just "fall through" to exit_procedure
bne $v0,$v1,loop
exit_procedure:
#set syscall to print_string, then set good_job string as arg
li $v0,4
la $a0,good_job
syscall
#exit program
li $v0,10
syscall
print_take_a_guess:
li $v0,4
la $a0,take_a_guess
syscall
jr $ra
read_int:
li $v0,5
syscall
jr $ra
|
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
|
#Nanoquery
|
Nanoquery
|
random = new(Nanoquery.Util.Random)
target = random.getInt(9) + 1
guess = 0
println "Guess a number between 1 and 10."
while not target = guess
guess = int(input())
end
println "That's right!"
|
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.
|
#Oberon-2
|
Oberon-2
|
MODULE GreatestSubsequentialSum;
IMPORT
Out,
Err,
IntStr,
ProgramArgs,
TextRider;
TYPE
IntSeq= POINTER TO ARRAY OF LONGINT;
PROCEDURE ShowUsage();
BEGIN
Out.String("Usage: GreatestSubsequentialSum {int}+");Out.Ln
END ShowUsage;
PROCEDURE Gss(iseq: IntSeq; VAR start, end, maxsum: LONGINT);
VAR
i, j, sum: LONGINT;
BEGIN
i := 0; maxsum := 0; start := 0; end := -1;
WHILE (i < LEN(iseq^)) DO
sum := 0; j := i;
WHILE (j < LEN(iseq^) - 1) DO
INC(sum,iseq[j]);
IF sum > maxsum THEN
maxsum := sum;
start := i;
end := j
END;
INC(j)
END;
INC(i)
END
END Gss;
PROCEDURE GetParams():IntSeq;
VAR
reader: TextRider.Reader;
iseq: IntSeq;
param: ARRAY 32 OF CHAR;
argc,i: LONGINT;
res: SHORTINT;
BEGIN
iseq := NIL;
reader := TextRider.ConnectReader(ProgramArgs.args);
IF reader # NIL THEN
argc := ProgramArgs.args.ArgNumber();
IF argc < 1 THEN
Err.String("There is no enough arguments.");Err.Ln;
ShowUsage;
HALT(0)
END;
reader.ReadLn; (* Skips program name *)
NEW(iseq,argc);
FOR i := 0 TO argc - 1 DO
reader.ReadLine(param);
IntStr.StrToInt(param,iseq[i],res);
END
END;
RETURN iseq
END GetParams;
PROCEDURE Do;
VAR
iseq: IntSeq;
start, end, sum, i: LONGINT;
BEGIN
iseq := GetParams();
Gss(iseq, start, end, sum);
i := start;
Out.String("[");
WHILE (i <= end) DO
Out.LongInt(iseq[i],0);
IF (i < end) THEN Out.Char(',') END;
INC(i)
END;
Out.String("]: ");Out.LongInt(sum,0);Out.Ln
END Do;
BEGIN
Do
END GreatestSubsequentialSum.
|
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)
|
#Go
|
Go
|
package main
import (
"fmt"
"math/rand"
"time"
)
const lower, upper = 1, 100
func main() {
fmt.Printf("Guess integer number from %d to %d: ", lower, upper)
rand.Seed(time.Now().Unix())
n := rand.Intn(upper-lower+1) + lower
for guess := n; ; {
switch _, err := fmt.Scan(&guess); {
case err != nil:
fmt.Println("\n", err, "So, bye.")
return
case guess < n:
fmt.Print("Too low. Try again: ")
case guess > n:
fmt.Print("Too high. Try again: ")
default:
fmt.Println("Well guessed!")
return
}
}
}
|
http://rosettacode.org/wiki/Happy_numbers
|
Happy numbers
|
From Wikipedia, the free encyclopedia:
A happy number is defined by the following process:
Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
Those numbers for which this process end in 1 are happy numbers,
while those numbers that do not end in 1 are unhappy numbers.
Task
Find and print the first 8 happy numbers.
Display an example of your output here on this page.
See also
The OEIS entry: The happy numbers: A007770
The OEIS entry: The unhappy numbers; A031177
|
#J
|
J
|
8{. (#~1=+/@(*:@(,.&.":))^:(1&~:*.4&~:)^:_ "0) 1+i.100
1 7 10 13 19 23 28 31
|
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.
|
#Swift
|
Swift
|
import Foundation
func haversine(lat1:Double, lon1:Double, lat2:Double, lon2:Double) -> Double {
let lat1rad = lat1 * Double.pi/180
let lon1rad = lon1 * Double.pi/180
let lat2rad = lat2 * Double.pi/180
let lon2rad = lon2 * Double.pi/180
let dLat = lat2rad - lat1rad
let dLon = lon2rad - lon1rad
let a = sin(dLat/2) * sin(dLat/2) + sin(dLon/2) * sin(dLon/2) * cos(lat1rad) * cos(lat2rad)
let c = 2 * asin(sqrt(a))
let R = 6372.8
return R * c
}
print(haversine(lat1:36.12, lon1:-86.67, lat2:33.94, lon2:-118.40))
|
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.
|
#Symsyn
|
Symsyn
|
lat1 : 36.12
lon1 : -86.67
lat2 : 33.94
lon2 : -118.4
dx : 0.
dy : 0.
dz : 0.
kms : 0.
{degtorad(lon2 - lon1)} lon1
{degtorad lat1} lat1
{degtorad lat2} lat2
{sin lat1 - sin lat2} dz
{cos lon1 * cos lat1 - cos lat2} dx
{sin lon1 * cos lat1} dy
{arcsin(sqrt(dx^2 + dy^2 + dz^2)/2) * 12745.6} kms
"'Haversine distance: ' kms ' kms'" []
|
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
|
#Hoon
|
Hoon
|
~& "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
|
#Sinclair_ZX81_BASIC
|
Sinclair ZX81 BASIC
|
10 FAST
20 LET N=0
30 LET H=0
40 LET N=N+1
50 LET N$=STR$ N
60 LET SD=0
70 FOR I=1 TO LEN N$
80 LET SD=SD+VAL N$(I)
90 NEXT I
100 IF N/SD<>INT (N/SD) THEN GOTO 40
110 LET H=H+1
120 IF H<=20 OR N>1000 THEN PRINT N
130 IF N>1000 THEN GOTO 150
140 GOTO 40
150 SLOW
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#PARI.2FGP
|
PARI/GP
|
plotinit(1, 1, 1, 1);
plotstring(1, "Goodbye, World!");
plotdraw([1, 0, 15]);
|
http://rosettacode.org/wiki/Hello_world/Graphical
|
Hello world/Graphical
|
Task
Display the string Goodbye, World! on a GUI object (alert box, plain window, text area, etc.).
Related task
Hello world/Text
|
#Pascal
|
Pascal
|
program HelloWorldGraphical;
uses
glib2, gdk2, gtk2;
var
window: PGtkWidget;
begin
gtk_init(@argc, @argv);
window := gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), 'Goodbye, World');
g_signal_connect (G_OBJECT (window),
'delete-event',
G_CALLBACK (@gtk_main_quit),
NULL);
gtk_widget_show_all (window);
gtk_main();
end.
|
http://rosettacode.org/wiki/Gray_code
|
Gray code
|
Gray code
Karnaugh maps
Create functions to encode a number to and decode a number from Gray code.
Display the normal binary representations, Gray code representations, and decoded Gray code values for all 5-bit binary numbers (0-31 inclusive, leading 0's not necessary).
There are many possible Gray codes. The following encodes what is called "binary reflected Gray code."
Encoding (MSB is bit 0, b is binary, g is Gray code):
if b[i-1] = 1
g[i] = not b[i]
else
g[i] = b[i]
Or:
g = b xor (b logically right shifted 1 time)
Decoding (MSB is bit 0, b is binary, g is Gray code):
b[0] = g[0]
for other bits:
b[i] = g[i] xor b[i-1]
Reference
Converting Between Gray and Binary Codes. It includes step-by-step animations.
|
#Liberty_BASIC
|
Liberty BASIC
|
for r =0 to 31
print " Decimal "; using( "###", r); " is ";
B$ =dec2Bin$( r)
print " binary "; B$; ". Binary "; B$;
G$ =Bin2Gray$( dec2Bin$( r))
print " is "; G$; " in Gray code, or ";
B$ =Gray2Bin$( G$)
print B$; " in pure binary."
next r
end
function Bin2Gray$( bin$) ' Given a binary number as a string, returns Gray code as a string.
g$ =left$( bin$, 1)
for i =2 to len( bin$)
bitA =val( mid$( bin$, i -1, 1))
bitB =val( mid$( bin$, i, 1))
AXorB =bitA xor bitB
g$ =g$ +str$( AXorB)
next i
Bin2Gray$ =g$
end function
function Gray2Bin$( g$) ' Given a Gray code as a string, returns equivalent binary num.
' as a string
gl =len( g$)
b$ =left$( g$, 1)
for i =2 to len( g$)
bitA =val( mid$( b$, i -1, 1))
bitB =val( mid$( g$, i, 1))
AXorB =bitA xor bitB
b$ =b$ +str$( AXorB)
next i
Gray2Bin$ =right$( b$, gl)
end function
function dec2Bin$( num) ' Given an integer decimal, returns binary equivalent as a string
n =num
dec2Bin$ =""
while ( num >0)
dec2Bin$ =str$( num mod 2) +dec2Bin$
num =int( num /2)
wend
if ( n >255) then nBits =16 else nBits =8
dec2Bin$ =right$( "0000000000000000" +dec2Bin$, nBits) ' Pad to 8 bit or 16 bit
end function
function bin2Dec( b$) ' Given a binary number as a string, returns decimal equivalent num.
t =0
d =len( b$)
for k =d to 1 step -1
t =t +val( mid$( b$, k, 1)) *2^( d -k)
next k
bin2Dec =t
end function
|
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!
|
#Batch_File
|
Batch File
|
@echo off
setlocal enabledelayedexpansion
set a=1
set b=woof
echo %a%
echo %b%
call :swap a b
echo %a%
echo %b%
goto :eof
:swap
set temp1=!%1!
set temp2=!%2!
set %1=%temp2%
set %2=%temp1%
goto :eof
|
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.
|
#C.23
|
C#
|
int[] values = new int[] {1,2,3,4,5,6,7,8,9,10};
int max = values.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.
|
#Axe
|
Axe
|
Lbl GCD
r₁→A
r₂→B
!If B
A
Return
End
GCD(B,A^B)
|
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.
|
#Scala
|
Scala
|
import java.io.{File, PrintWriter}
object GloballyReplaceText extends App {
val (charsetName, fileNames) = ("UTF8", Seq("file1.txt", "file2.txt"))
for (fileHandle <- fileNames.map(new File(_)))
new PrintWriter(fileHandle, charsetName) {
print(scala.io.Source.fromFile(fileHandle, charsetName).mkString
.replace("Goodbye London!", "Hello New York!"))
close()
}
}
|
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.
|
#Sed
|
Sed
|
sed -i 's/Goodbye London!/Hello New York!/g' a.txt b.txt c.txt
|
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.
|
#Seed7
|
Seed7
|
$ include "seed7_05.s7i";
include "getf.s7i";
const proc: main is func
local
var string: fileName is "";
var string: content is "";
begin
for fileName range [] ("a.txt", "b.txt", "c.txt") do
content := getf(fileName);
content := replace(content, "Goodbye London!", "Hello New York!");
putf(fileName, content);
end for;
end func;
|
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).
|
#C.23
|
C#
|
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Hailstone
{
class Program
{
public static List<int> hs(int n,List<int> seq)
{
List<int> sequence = seq;
sequence.Add(n);
if (n == 1)
{
return sequence;
}else{
int newn = (n % 2 == 0) ? n / 2 : (3 * n) + 1;
return hs(newn, sequence);
}
}
static void Main(string[] args)
{
int n = 27;
List<int> sequence = hs(n,new List<int>());
Console.WriteLine(sequence.Count + " Elements");
List<int> start = sequence.GetRange(0, 4);
List<int> end = sequence.GetRange(sequence.Count - 4, 4);
Console.WriteLine("Starting with : " + string.Join(",", start) + " and ending with : " + string.Join(",", end));
int number = 0, longest = 0;
for (int i = 1; i < 100000; i++)
{
int count = (hs(i, new List<int>())).Count;
if (count > longest)
{
longest = count;
number = i;
}
}
Console.WriteLine("Number < 100000 with longest Hailstone seq.: " + number + " with length of " + longest);
}
}
}
|
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).
|
#J
|
J
|
hamming=: {. (/:~@~.@] , 2 3 5 * {)/@(1x ,~ i.@-)
|
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
|
#Nemerle
|
Nemerle
|
using System;
using System.Console;
module Guess
{
Main() : void
{
def rand = Random();
def x = rand.Next(1, 11); // returns 1 <= x < 11
mutable guess = 0;
do
{
WriteLine("Guess a nnumber between 1 and 10:");
guess = Int32.Parse(ReadLine());
} while (guess != x);
WriteLine("Well guessed!");
}
}
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#OCaml
|
OCaml
|
let maxsubseq =
let rec loop sum seq maxsum maxseq = function
| [] -> maxsum, List.rev maxseq
| x::xs ->
let sum = sum + x
and seq = x :: seq in
if sum < 0 then
loop 0 [] maxsum maxseq xs
else if sum > maxsum then
loop sum seq sum seq xs
else
loop sum seq maxsum maxseq xs
in
loop 0 [] 0 []
let _ =
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)
|
#Groovy
|
Groovy
|
def rand = new Random() // java.util.Random
def range = 1..100 // Range (inclusive)
def number = rand.nextInt(range.size()) + range.from // get a random number in the range
println "The number is in ${range.toString()}" // print the range
def guess
while (guess != number) { // keep running until correct guess
try {
print 'Guess the number: '
guess = System.in.newReader().readLine() as int // read the guess in as int
switch (guess) { // check the guess against number
case { it < number }: println 'Your guess is too low'; break
case { it > number }: println 'Your guess is too high'; break
default: println 'Your guess is spot on!'; break
}
} catch (NumberFormatException ignored) { // catches all input that is not a number
println 'Please enter a number!'
}
}
|
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
|
#Java
|
Java
|
import java.util.HashSet;
public class Happy{
public static boolean happy(long number){
long m = 0;
int digit = 0;
HashSet<Long> cycle = new HashSet<Long>();
while(number != 1 && cycle.add(number)){
m = 0;
while(number > 0){
digit = (int)(number % 10);
m += digit*digit;
number /= 10;
}
number = m;
}
return number == 1;
}
public static void main(String[] args){
for(long num = 1,count = 0;count<8;num++){
if(happy(num)){
System.out.println(num);
count++;
}
}
}
}
|
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.
|
#tbas
|
tbas
|
OPTION angle radians ' the default
SUB haversine(lat1, lon1, lat2, lon2)
DIM EarthRadiusKm = 6372.8 ' Earth radius in kilometers
DIM latRad1 = RAD(lat1)
DIM latRad2 = RAD(lat2)
DIM lonRad1 = RAD(lon1)
DIM lonRad2 = RAD(lon2)
DIM _diffLa = latRad2 - latRad1
DIM _doffLo = lonRad2 - lonRad1
DIM sinLaSqrd = SIN(_diffLa / 2) ^ 2
DIM sinLoSqrd = SIN(_doffLo / 2) ^ 2
DIM computation = asin(sqrt(sinLaSqrd + COS(latRad1) * COS(latRad2) * sinLoSqrd))
RETURN 2 * EarthRadiusKm * computation
END SUB
PRINT USING "Nashville International Airport to Los Angeles International Airport ####.########### km", haversine(36.12, -86.67, 33.94, -118.40)
PRINT USING "Perth, WA Australia to Baja California, Mexico #####.########### km", haversine(-31.95, 115.86, 31.95, -115.86)
|
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
|
#HPPPL
|
HPPPL
|
PRINT("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
|
#Swift
|
Swift
|
struct Harshad: Sequence, IteratorProtocol {
private var i = 0
mutating func next() -> Int? {
while true {
i += 1
if i % Array(String(i)).map(String.init).compactMap(Int.init).reduce(0, +) == 0 {
return i
}
}
}
}
print("First 20: \(Array(Harshad().prefix(20)))")
print("First over a 1000: \(Harshad().first(where: { $0 > 1000 })!)")
|
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
|
#Perl
|
Perl
|
use strict;
use warnings;
use Tk;
my $main = MainWindow->new;
$main->Label(-text => 'Goodbye, World')->pack;
MainLoop();
|
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
|
#Phix
|
Phix
|
include pGUI.e
IupOpen()
IupMessage("Bye","Goodbye, World!")
IupClose()
|
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.
|
#Limbo
|
Limbo
|
implement Gray;
include "sys.m"; sys: Sys;
print: import sys;
include "draw.m";
Gray: module {
init: fn(nil: ref Draw->Context, args: list of string);
# Export gray and grayinv so that this module can be used as either a
# standalone program or as a library:
gray: fn(n: int): int;
grayinv: fn(n: int): int;
};
init(nil: ref Draw->Context, args: list of string)
{
sys = load Sys Sys->PATH;
for(i := 0; i < 32; i++) {
g := gray(i);
f := grayinv(g);
print("%2d %5s %2d %5s %5s %2d\n", i, binstr(i), g, binstr(g), binstr(f), f);
}
}
gray(n: int): int
{
return n ^ (n >> 1);
}
grayinv(n: int): int
{
r := 0;
while(n) {
r ^= n;
n >>= 1;
}
return r;
}
binstr(n: int): string
{
if(!n)
return "0";
s := "";
while(n) {
s = (string (n&1)) + s;
n >>= 1;
}
return s;
}
|
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.
|
#Lobster
|
Lobster
|
def grey_encode(n) -> int:
return n ^ (n >> 1)
def grey_decode(n) -> int:
var p = n
n = n >> 1
while n != 0:
p = p ^ n
n = n >> 1
return p
for(32) i:
let g = grey_encode(i)
let b = grey_decode(g)
print(number_to_string(i, 10, 2) + " : " +
number_to_string(i, 2, 5) + " ⇾ " +
number_to_string(g, 2, 5) + " ⇾ " +
number_to_string(b, 2, 5) + " : " +
number_to_string(b, 10, 2))
|
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!
|
#BaCon
|
BaCon
|
x = 1
y$ = "hello"
SWAP x, y$
PRINT y$
|
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.
|
#C.2B.2B
|
C++
|
#include <algorithm> //std::max_element
#include <iterator> //std::begin and std::end
#include <functional> //std::less
template<class It, class Comp = std::less<>>
//requires ForwardIterator<It> && Compare<Comp>
constexpr auto max_value(It first, It last, Comp compare = std::less{})
{
//Precondition: first != last
return *std::max_element(first, last, compare);
}
template<class C, class Comp = std::less<>>
//requires Container<C> && Compare<Comp>
constexpr auto max_value(const C& container, Comp compare = std::less{})
{
//Precondition: !container.empty()
using std::begin; using std::end;
return max_value(begin(container), end(container), compare);
}
|
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.
|
#BASIC
|
BASIC
|
FUNCTION gcd(a%, b%)
IF a > b THEN
factor = a
ELSE
factor = b
END IF
FOR l = factor TO 1 STEP -1
IF a MOD l = 0 AND b MOD l = 0 THEN
gcd = l
END IF
NEXT l
gcd = 1
END FUNCTION
|
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.
|
#Sidef
|
Sidef
|
var names = %w(
a.txt
b.txt
c.txt
)
names.map{ File(_) }.each { |file|
say file.edit { |line|
line.gsub("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.
|
#Tcl
|
Tcl
|
package require Tcl 8.5
package require fileutil
# Parameters to the replacement
set from "Goodbye London!"
set to "Hello New York!"
# Which files to replace
set fileList [list a.txt b.txt c.txt]
# Make a command fragment that performs the replacement on a supplied string
set replacementCmd [list string map [list $from $to]]
# Apply the replacement to the contents of each file
foreach filename $fileList {
fileutil::updateInPlace $filename $replacementCmd
}
|
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.
|
#Transd
|
Transd
|
#lang transd
MainModule: {
_start: (λ
(with files ["a.txt" "b.txt" "c.txt"] fs FileStream()
(for f in files do
(open-r fs f)
(with s (replace (read-text fs)
"Goodbye London!" "Hello New York!")
(close fs)
(open-w fs f)
(write fs (to-bytes s) (size s)))))
)
}
|
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).
|
#C.2B.2B
|
C++
|
#include <iostream>
#include <vector>
#include <utility>
std::vector<int> hailstone(int i)
{
std::vector<int> v;
while(true){
v.push_back(i);
if (1 == i) break;
i = (i % 2) ? (3 * i + 1) : (i / 2);
}
return v;
}
std::pair<int,int> find_longest_hailstone_seq(int n)
{
std::pair<int, int> maxseq(0, 0);
int l;
for(int i = 1; i < n; ++i){
l = hailstone(i).size();
if (l > maxseq.second) maxseq = std::make_pair(i, l);
}
return maxseq;
}
int main () {
// Use the routine to show that the hailstone sequence for the number 27
std::vector<int> h27;
h27 = hailstone(27);
// has 112 elements
int l = h27.size();
std::cout << "length of hailstone(27) is " << l;
// starting with 27, 82, 41, 124 and
std::cout << " first four elements of hailstone(27) are ";
std::cout << h27[0] << " " << h27[1] << " "
<< h27[2] << " " << h27[3] << std::endl;
// ending with 8, 4, 2, 1
std::cout << " last four elements of hailstone(27) are "
<< h27[l-4] << " " << h27[l-3] << " "
<< h27[l-2] << " " << h27[l-1] << std::endl;
std::pair<int,int> m = find_longest_hailstone_seq(100000);
std::cout << "the longest hailstone sequence under 100,000 is " << m.first
<< " with " << m.second << " elements." <<std::endl;
return 0;
}
|
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).
|
#Java
|
Java
|
import java.math.BigInteger;
import java.util.PriorityQueue;
final class Hamming {
private static BigInteger THREE = BigInteger.valueOf(3);
private static BigInteger FIVE = BigInteger.valueOf(5);
private static void updateFrontier(BigInteger x,
PriorityQueue<BigInteger> pq) {
pq.offer(x.shiftLeft(1));
pq.offer(x.multiply(THREE));
pq.offer(x.multiply(FIVE));
}
public static BigInteger hamming(int n) {
if (n <= 0)
throw new IllegalArgumentException("Invalid parameter");
PriorityQueue<BigInteger> frontier = new PriorityQueue<BigInteger>();
updateFrontier(BigInteger.ONE, frontier);
BigInteger lowest = BigInteger.ONE;
for (int i = 1; i < n; i++) {
lowest = frontier.poll();
while (frontier.peek().equals(lowest))
frontier.poll();
updateFrontier(lowest, frontier);
}
return lowest;
}
public static void main(String[] args) {
System.out.print("Hamming(1 .. 20) =");
for (int i = 1; i < 21; i++)
System.out.print(" " + hamming(i));
System.out.println("\nHamming(1691) = " + hamming(1691));
System.out.println("Hamming(1000000) = " + hamming(1000000));
}
}
|
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
|
#NetRexx
|
NetRexx
|
/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
guessThis = (Math.random * 10 + 1) % 1
guess = -1
prompt = [ -
'Try guessing a number between 1 and 10', -
'Wrong; try again...' -
]
promptIdx = int 0
loop label g_ until guess = guessThis
say prompt[promptIdx]
promptIdx = 1
parse ask guess .
if guess = guessThis then do
say 'Well guessed!' guess 'is the correct number.'
leave g_
end
end g_
return
|
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
|
#NewLISP
|
NewLISP
|
; guess-number.lsp
; oofoe 2012-01-19
; http://rosettacode.org/wiki/Guess_the_number
(seed (time-of-day)) ; Initialize random number generator from clock.
(setq number (+ 1 (rand 10)))
(println "I'm thinking of a number between 1 and 10. Can you guess it?")
(print "Type in your guess and hit [enter]: ")
(while (!= number (int (read-line))) (print "Nope! Try again: "))
(println "Well guessed! Congratulations!")
(exit)
|
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.
|
#Oz
|
Oz
|
declare
fun {MaxSubSeq Xs}
fun {Step [Sum0 Seq0 MaxSum MaxSeq] X}
Sum = Sum0 + X
Seq = X|Seq0
in
if Sum > MaxSum then
%% found new maximum
[Sum Seq Sum Seq]
elseif Sum < 0 then
%% discard negative subseqs
[0 nil MaxSum MaxSeq]
else
[Sum Seq MaxSum MaxSeq]
end
end
[_ _ _ MaxSeq] = {FoldL Xs Step [0 nil 0 nil]}
in
{Reverse MaxSeq}
end
in
{Show {MaxSubSeq [~1 ~2 3 5 6 ~2 ~1 4 ~4 2 1]}}
|
http://rosettacode.org/wiki/Greatest_subsequential_sum
|
Greatest subsequential sum
|
Task
Given a sequence of integers, find a continuous subsequence which maximizes the sum of its elements, that is, the elements of no other single subsequence add up to a value larger than this one.
An empty subsequence is considered to have the sum of 0; thus if all elements are negative, the result must be the empty sequence.
|
#PARI.2FGP
|
PARI/GP
|
grsub(v)={
my(mn=1,mx=#v,r=0,at,c);
if(vecmax(v)<=0,return([1,0]));
while(v[mn]<=0,mn++);
while(v[mx]<=0,mx--);
for(a=mn,mx,
c=0;
for(b=a,mx,
c+=v[b];
if(c>r,r=c;at=[a,b])
)
);
at
};
|
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)
|
#Haskell
|
Haskell
|
import Control.Monad
import System.Random
-- Repeat the action until the predicate is true.
until_ act pred = act >>= pred >>= flip unless (until_ act pred)
answerIs ans guess =
case compare ans guess of
LT -> putStrLn "Too high. Guess again." >> return False
EQ -> putStrLn "You got it!" >> return True
GT -> putStrLn "Too low. Guess again." >> return False
-- Repeatedly read until the input *starts* with a number. (Since
-- we use "reads" we allow garbage to follow it, though.)
ask = do line <- getLine
case reads line of
((num,_):_) -> return num
otherwise -> putStrLn "Please enter a number." >> ask
main = do
ans <- randomRIO (1,100) :: IO Int
putStrLn "Try to guess my secret number between 1 and 100."
ask `until_` answerIs ans
|
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
|
#JavaScript
|
JavaScript
|
function happy(number) {
var m, digit ;
var cycle = [] ;
while(number != 1 && cycle[number] !== true) {
cycle[number] = true ;
m = 0 ;
while (number > 0) {
digit = number % 10 ;
m += digit * digit ;
number = (number - digit) / 10 ;
}
number = m ;
}
return (number == 1) ;
}
var cnt = 8 ;
var number = 1 ;
while(cnt-- > 0) {
while(!happy(number))
number++ ;
document.write(number + " ") ;
number++ ;
}
|
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.
|
#Tcl
|
Tcl
|
package require Tcl 8.5
proc haversineFormula {lat1 lon1 lat2 lon2} {
set rads [expr atan2(0,-1)/180]
set R 6372.8 ;# In kilometers
set dLat [expr {($lat2-$lat1) * $rads}]
set dLon [expr {($lon2-$lon1) * $rads}]
set lat1 [expr {$lat1 * $rads}]
set lat2 [expr {$lat2 * $rads}]
set a [expr {sin($dLat/2)**2 + sin($dLon/2)**2*cos($lat1)*cos($lat2)}]
set c [expr {2*asin(sqrt($a))}]
return [expr {$R * $c}]
}
# Don't bother with too much inappropriate accuracy!
puts [format "distance=%.1f km" [haversineFormula 36.12 -86.67 33.94 -118.40]]
|
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