task_url stringlengths 30 116 | task_name stringlengths 2 86 | task_description stringlengths 0 14.4k | language_url stringlengths 2 53 | language_name stringlengths 1 52 | code stringlengths 0 61.9k |
|---|---|---|---|---|---|
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #Sidef | Sidef | func identity_matrix(n) {
n.of { |i|
n.of { |j|
i == j ? 1 : 0
}
}
}
for n (ARGV ? ARGV.map{.to_i} : [4, 5, 6]) {
say "\n#{n}:"
for row (identity_matrix(n)) {
say row.join(' ')
}
} |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Sidef | Sidef | var a = read("a: ", Number);
var b = read("b: ", Number);
if (a < b) {
say 'Lower';
}
elsif (a == b) {
say 'Equal';
}
elsif (a > b) {
say 'Greater';
} |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Slate | Slate | [ |:a :b |
( a > b ) ifTrue: [ inform: 'a greater than b\n' ].
( a < b ) ifTrue: [ inform: 'a less than b\n' ].
( a = b ) ifTrue: [ inform: 'a is equal to b\n' ].
] applyTo: {Integer readFrom: (query: 'Enter a: '). Integer readFrom: (query: 'Enter b: ')}. |
http://rosettacode.org/wiki/HTTP | HTTP | Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| #Icon_and_Unicon | Icon and Unicon |
link cfunc
procedure main(arglist)
get(arglist[1])
end
procedure get(url)
local f, host, port, path
url ? {
="http://" | ="HTTP://"
host := tab(upto(':/') | 0)
if not (=":" & (port := integer(tab(upto('/'))))) then port := 80
if pos(0) then path := "/" else path := tab(0... |
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #Lua | Lua |
local fmt, write=string.format,io.write
local hof=coroutine.wrap(function()
local yield=coroutine.yield
local a={1,1}
yield(a[1], 1)
yield(a[2], 2)
local n=a[#a]
repeat
n=a[n]+a[1+#a-n]
a[#a+1]=n
yield(n, #a)
until false
end)
local mallows, mdiv=0,0
for p=1,20 do
local max, div, num, last, fdiv=0,0,0,... |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Frink | Frink |
staticJava["java.lang.System","err"].println["Goodbye, World!"]
|
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Genie | Genie | [indent=4]
/*
Hello, to Standard error, in Genie
valac helloStderr.gs
*/
init
stderr.printf("%s\n", "Goodbye, World!") |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Go | Go | package main
func main() { println("Goodbye, World!") } |
http://rosettacode.org/wiki/Hofstadter_Q_sequence | Hofstadter Q sequence | Hofstadter Q sequence
Q
(
1
)
=
Q
(
2
)
=
1
,
Q
(
n
)
=
Q
(
n
−
Q
(
n
−
1
)
)
+
Q
(
n
−
Q
(
n
−
2
)
)
,
n
>
2.
{\displaystyle {\begin{aligned}Q(1)&=Q(2)=1,\\Q(n)&=Q{\big (}n-Q(n-1){\big )}+Q{\big (}n-Q(n-2){\big )},\quad n>2.\end{aligned}}}
It is defined like the Fibonacc... | #Factor | Factor | ( scratchpad ) : next ( seq -- newseq )
dup 2 tail* over length [ swap - ] curry map
[ dupd swap nth ] map 0 [ + ] reduce suffix ;
( scratchpad ) { 1 1 } 1000 [ next ] times dup 10 head . 999 swap nth .
{ 1 1 2 3 3 4 5 5 6 6 }
502 |
http://rosettacode.org/wiki/Hofstadter_Q_sequence | Hofstadter Q sequence | Hofstadter Q sequence
Q
(
1
)
=
Q
(
2
)
=
1
,
Q
(
n
)
=
Q
(
n
−
Q
(
n
−
1
)
)
+
Q
(
n
−
Q
(
n
−
2
)
)
,
n
>
2.
{\displaystyle {\begin{aligned}Q(1)&=Q(2)=1,\\Q(n)&=Q{\big (}n-Q(n-1){\big )}+Q{\big (}n-Q(n-2){\big )},\quad n>2.\end{aligned}}}
It is defined like the Fibonacc... | #Fermat | Fermat | Func Hq(n) = if n<2 then 1 else
Array qq[n+1];
qq[1] := 1;
qq[2] := 1;
for i = 3, n do
qq[i]:=qq[i-qq[i-1]]+qq[i-qq[i-2]]
od;
Return(qq[n]);
fi;
.
for i=1 to 10 do !Hq(i);!' ' od;
Hq(1000) |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Ring | Ring |
n = 12
hick = 0
decimals(8)
for i = 1 to n
see "h(" + string(i) + ") = "
see "" + hickersonSeries(i) + " "
if nearly(hick) = 1 see "nearly integer" + nl
else see "not nearly integer" + nl ok
next
func hickersonSeries nr
hick = fact(nr) / (2 * pow(log(2), nr+1))
return hick
func fact... |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Ruby | Ruby | require "bigdecimal"
LN2 = BigMath::log(2,16) #Use LN2 = Math::log(2) to see the difference with floats
FACTORIALS = Hash.new{|h,k| h[k] = k * h[k-1]}
FACTORIALS[0] = 1
def hickerson(n)
FACTORIALS[n] / (2 * LN2 ** (n+1))
end
def nearly_int?(n)
int = n.round
n.between?(int - 0.1, int + 0.1)
end
1.upto(17)... |
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
| #AArch64_Assembly | AArch64 Assembly | .equ STDOUT, 1
.equ SVC_WRITE, 64
.equ SVC_EXIT, 93
.text
.global _start
_start:
stp x29, x30, [sp, -16]!
mov x0, #STDOUT
ldr x1, =msg
mov x2, 13
mov x8, #SVC_WRITE
mov x29, sp
svc #0 // write(stdout, msg, 13);
ldp x29, x30, [sp], 16
mov x0, #0
mov x8, #SVC_EXIT
svc #0 // exit(0);
msg: .ascii "Hello Wo... |
http://rosettacode.org/wiki/Heronian_triangles | Heronian triangles | Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
+
b
+
c
2
.
{\displaystyle s... | #FreeBASIC | FreeBASIC | ' version 02-05-2016
' compile with: fbc -s console
#Macro header
Print
Print " a b c s area"
Print "-----------------------------------"
#EndMacro
Type triangle
Dim As UInteger a
Dim As UInteger b
Dim As UInteger c
Dim As UInteger s
Dim As UInteger area
End Typ... |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #Burlesque | Burlesque |
blsq ) {1 2 3 4}{5.+}m[
{6 7 8 9}
|
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Java | Java | import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class HelloWorld{
public static void main(String[] args) throws IOException{
ServerSocket listener = new ServerSocket(8080);
while(true){
Socket sock = listener.accept();
new Prin... |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #JavaScript | JavaScript | var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Goodbye, World!\n');
}).listen(8080, '127.0.0.1'); |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Perl | Perl | $address = <<END;
1, High Street,
$town_name,
West Midlands.
WM4 5HD.
END |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Phix | Phix | string ts1 = """
this
"string"\thing"""
string ts2 = """this
"string"\thing"""
string ts3 = """
_____________this
"string"\thing"""
string ts4 = `
this
"string"\thing`
string ts5 = `this
"string"\thing`
string ts6 = `
_____________this
"string"\thing`
string ts7 = "this\n\"string\"... |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #PHP | PHP | $address = <<<END
1, High Street,
$town_name,
West Midlands.
WM4 5HD.
END; |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #PicoLisp | PicoLisp | (out "file.txt" # Write to "file.txt"
(prinl "### This is before the text ###")
(here "TEXT-END")
(prinl "### This is after the text ###") )
"There must be some way out of here", said the joker to the thief
"There's too much confusion, I can't get no relief"
TEXT-END
(in "file.txt" (ec... |
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #SenseTalk | SenseTalk | // HistoryVariable.script
properties
history: [], -- a list of all historical values
asTextFormat:"[[the last item of my history]]" -- always display the last value
end properties
to set newValue
push newValue nested into my history
end set
to rollback
pop my history
return it
end rollback
|
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #Sidef | Sidef | class HistoryVar(v) {
has history = []
has variable = v
method ≔(value) {
history << variable
variable = value
}
method to_s {
"#{variable}"
}
method AUTOLOAD(_, name, *args) {
variable.(name)(args...)
}
}
var foo = HistoryVar(0)
foo ≔ 1
foo ≔ ... |
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #Smalltalk | Smalltalk | Object subclass:'HVar'
instanceVariableNames:'values'
classVariableNames:''
poolDictionaries:''
category:'example'.
!
!HVar methodsFor:'accessing'!
<-- value
(values ifNil:[values := OrderedCollection new]) add:value.
^ value
!
value
^ values last
!
undo
values removeLast.
!
... |
http://rosettacode.org/wiki/Hofstadter_Figure-Figure_sequences | Hofstadter Figure-Figure sequences | These two sequences of positive integers are defined as:
R
(
1
)
=
1
;
S
(
1
)
=
2
R
(
n
)
=
R
(
n
−
1
)
+
S
(
n
−
1
)
,
n
>
1.
{\displaystyle {\begin{aligned}R(1)&=1\ ;\ S(1)=2\\R(n)&=R(n-1)+S(n-1),\quad n>1.\end{aligned}}}
The sequence
S
(
n
)
{\displaystyle S(n)}
is further... | #Phix | Phix | with javascript_semantics
sequence F = {1,3,7},
S = {2,4,5,6}
integer fmax = 3 -- (ie F[3], ==7, already in S)
forward function ffs(integer n)
function ffr(integer n)
integer l = length(F)
while n>l do
F &= F[l]+ffs(l)
l += 1
end while
return F[n]
end function
function ffs... |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Nim | Nim | # You can also just use `reversed` proc from stdlib `algorithm` module
iterator reversed[T](x: openArray[T]): T =
for i in countdown(x.high, x.low):
yield x[i]
proc horner[T](coeffs: openArray[T], x: T): int =
for c in reversed(coeffs):
result = result * x + c
echo horner([-19, 7, -4, 6], 3) |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Oberon-2 | Oberon-2 |
MODULE HornerRule;
IMPORT
Out;
TYPE
Coefs = POINTER TO ARRAY OF LONGINT;
VAR
coefs: Coefs;
PROCEDURE Eval(coefs: ARRAY OF LONGINT;size,x: LONGINT): LONGINT;
VAR
i,acc: LONGINT;
BEGIN
acc := 0;
FOR i := LEN(coefs) - 1 TO 0 BY -1 DO
acc := acc * x + coefs[i]
END;
RETURN acc
END Eval;
BEGIN
NEW... |
http://rosettacode.org/wiki/Hilbert_curve | Hilbert curve |
Task
Produce a graphical or ASCII-art representation of a Hilbert curve of at least order 3.
| #Processing | Processing | int iterations = 7;
float strokeLen = 600;
int angleDeg = 90;
String axiom = "L";
StringDict rules = new StringDict();
String sentence = axiom;
int xo, yo;
void setup() {
size(700, 700);
xo= 50;
yo = height - 50;
strokeWeight(1);
noFill();
rules.set("L", "+RF-LFL-FR+");
rules.set("R", "-LF+RFR+FL-")... |
http://rosettacode.org/wiki/Holidays_related_to_Easter | Holidays related to Easter | Task
Calculate the dates of:
Easter
Ascension Thursday
Pentecost
Trinity Sunday
Corpus Christi feast (for Catholic)
All Saints' Sunday (for Orthodox)
As an example, calculate for the first year of each century from;
years 400 to 2100 CE and for
years 2010 to 2020 CE.
Note
... | #Mathematica.2FWolfram_Language | Mathematica/Wolfram Language | Needs["Calendar`"];DateFormat[x_]:=DateString[x,{"DayNameShort"," ","DayShort"," ","MonthName"}]
Map[StringJoin[ToString[#]," Easter: ",DateFormat[EasterSunday[#]],
", Ascension: ",DateFormat[DaysPlus[EasterSunday[#],39]],
", Pentecost: ",DateFormat[DaysPlus[EasterSunday[#],49]],
", Trinity: ",DateFormat[DaysPlus[Easte... |
http://rosettacode.org/wiki/Horizontal_sundial_calculations | Horizontal sundial calculations | Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island, aka Ernest Legouve Reef), wit... | #Octave | Octave | lat = input("Enter latitude: ");
lng = input("Enter longitude: ");
ref = input("Enter legal meridian: ");
slat = sind(lat);
printf("sine of latitude: %.3f\n", slat);
printf("diff longitude: %.3f\n\n", lng - ref);
printf("Hour, sun hour angle, dial hour line angle from 6am to 6pm\n");
hras = [-6:6] .* 15.0 .- lng .+ r... |
http://rosettacode.org/wiki/Huffman_coding | Huffman coding | Huffman encoding is a way to assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.
For example, if you use letters as symbols and have details of the frequency of occurrence of those letters in typical strings, then you could just encode each letter wi... | #Prolog | Prolog | huffman :-
L = 'this is an example for huffman encoding',
atom_chars(L, LA),
msort(LA, LS),
packList(LS, PL),
sort(PL, PLS),
build_tree(PLS, A),
coding(A, [], C),
sort(C, SC),
format('Symbol~t Weight~t~30|Code~n'),
maplist(print_code, SC).
build_tree([[V1|R1], [V2|R2]|T], AF) :-
V is V1 + V2,
A = [V, ... |
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #Sinclair_ZX81_BASIC | Sinclair ZX81 BASIC | 10 INPUT S
20 DIM M(S,S)
30 FOR I=1 TO S
40 LET M(I,I)=1
50 NEXT I
60 FOR I=1 TO S
70 SCROLL
80 FOR J=1 TO S
90 PRINT M(I,J);
100 NEXT J
110 PRINT
120 NEXT I |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Smalltalk | Smalltalk | | a b |
'a = ' display. a := (stdin nextLine asInteger).
'b = ' display. b := (stdin nextLine asInteger).
( a > b ) ifTrue: [ 'a greater than b' displayNl ].
( a < b ) ifTrue: [ 'a less than b' displayNl ].
( a = b ) ifTrue: [ 'a is equal to b' displayNl ]. |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #SNOBOL4 | SNOBOL4 | * # Get user input
output = 'Enter X,Y:'
trim(input) break(',') . x ',' rem . y
output = lt(x,y) x ' is less than ' y :s(end)
output = eq(x,y) x ' is equal to ' y :s(end)
output = gt(x,y) x ' is greater than ' y
end |
http://rosettacode.org/wiki/HTTP | HTTP | Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| #J | J | require'web/gethttp'
gethttp 'http://www.rosettacode.org'
|
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | a[1] := 1; a[2] := 1;
a[n_] := a[n] = a[a[n-1]] + a[n-a[n-1]]
Map[Print["Max value: ",Max[Table[a[n]/n//N,{n,2^#,2^(#+1)}]]," for n between 2^",#," and 2^",(#+1)]& , Range[19]]
n=2^20; While[(a[n]/n//N)<0.55,n--]; Print["Mallows number: ",n] |
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #MATLAB_.2F_Octave | MATLAB / Octave | function Q = HCsequence(N)
Q = zeros(1,N);
Q(1:2) = 1;
for n = 3:N,
Q(n) = Q(Q(n-1))+Q(n-Q(n-1));
end;
end; |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Groovy | Groovy | System.err.println("Goodbye, World!") |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Haskell | Haskell | import System.IO
main = hPutStrLn stderr "Goodbye, World!" |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Huginn | Huginn | #! /bin/sh
exec huginn --no-argv -E "${0}" "${@}"
#! huginn
import OperatingSystem as os;
main() {
os.stderr().write( "Goodbye, World!\n" );
return ( 0 );
} |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Icon_and_Unicon | Icon and Unicon | procedure main()
write(&errout, "Goodbye World" )
end |
http://rosettacode.org/wiki/Hofstadter_Q_sequence | Hofstadter Q sequence | Hofstadter Q sequence
Q
(
1
)
=
Q
(
2
)
=
1
,
Q
(
n
)
=
Q
(
n
−
Q
(
n
−
1
)
)
+
Q
(
n
−
Q
(
n
−
2
)
)
,
n
>
2.
{\displaystyle {\begin{aligned}Q(1)&=Q(2)=1,\\Q(n)&=Q{\big (}n-Q(n-1){\big )}+Q{\big (}n-Q(n-2){\big )},\quad n>2.\end{aligned}}}
It is defined like the Fibonacc... | #Forth | Forth | 100000 constant N
: q ( n -- addr ) cells here + ;
: qinit
1 0 q !
1 1 q !
N 2 do
i i 1- q @ - q @
i i 2 - q @ - q @
+ i q !
loop ;
: flips
." flips: "
0 N 1 do
i q @ i 1- q @ < if 1+ then
loop . cr ;
: qprint ( n -- )
0 do i q @ . loop cr ;
qinit
10 qprint
999 q @ . cr
flips
b... |
http://rosettacode.org/wiki/Hofstadter_Q_sequence | Hofstadter Q sequence | Hofstadter Q sequence
Q
(
1
)
=
Q
(
2
)
=
1
,
Q
(
n
)
=
Q
(
n
−
Q
(
n
−
1
)
)
+
Q
(
n
−
Q
(
n
−
2
)
)
,
n
>
2.
{\displaystyle {\begin{aligned}Q(1)&=Q(2)=1,\\Q(n)&=Q{\big (}n-Q(n-1){\big )}+Q{\big (}n-Q(n-2){\big )},\quad n>2.\end{aligned}}}
It is defined like the Fibonacc... | #Fortran | Fortran |
Calculate the Hofstadter Q-sequence, using a big array rather than recursion.
INTEGER ENUFF
PARAMETER (ENUFF = 100000)
INTEGER Q(ENUFF) !Lots of memory these days.
Q(1) = 1 !Initial values as per the definition.
Q(2) = 1
Q(3:) = -123456789!This will surely cause trouble!
D... |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Rust | Rust |
use decimal::d128;
use factorial::Factorial;
fn hickerson(n: u64) -> d128 {
d128::from(n.factorial()) / (d128!(2) * (d128!(2).ln().pow(d128::from(n + 1))))
}
// Some details on floating-points numbers can be found at https://cheats.rs/#basic-types
fn main() {
for i in 1..18 {
let h = hickerson(i);... |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Scala | Scala | import scala.annotation.tailrec
object Hickerson extends App {
def almostInteger(n: Int): Boolean = {
def ln2 = BigDecimal("0.69314718055994530941723212145818")
def div: BigDecimal = ln2.pow(n + 1) * 2
def factorial(num: Int): Long = {
@tailrec
def accumulated(acc: Long, n: Long): Long... |
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
| #ABAP | ABAP | REPORT zgoodbyeworld.
WRITE 'Hello world!'. |
http://rosettacode.org/wiki/Heronian_triangles | Heronian triangles | Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
+
b
+
c
2
.
{\displaystyle s... | #FutureBasic | FutureBasic |
include "ConsoleWindow"
// Set width of tabs
def tab 10
local fn gcd( a as long, b as long )
dim as long result
if ( b != 0 )
result = fn gcd( b, a mod b)
else
result = abs(a)
end if
end fn = result
begin globals
dim as long triangleInfo( 600, 4 )
end globals
local fn CalculateHeronianTriangles( numbe... |
http://rosettacode.org/wiki/Heronian_triangles | Heronian triangles | Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
+
b
+
c
2
.
{\displaystyle s... | #Go | Go | package main
import (
"fmt"
"math"
"sort"
)
const (
n = 200
header = "\nSides P A"
)
func gcd(a, b int) int {
leftover := 1
var dividend, divisor int
if (a > b) { dividend, divisor = a, b } else { dividend, divisor = b, a }
for (leftover != 0) {
leftover = ... |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #C | C | void myFuncSimple( void (*funcParameter)(void) )
{
/* ... */
(*funcParameter)(); /* Call the passed function. */
funcParameter(); /* Same as above with slight different syntax. */
/* ... */
} |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Jsish | Jsish | prompt$ jsish
# require('Jsi_Websrv');
1.01
# Jsi_Websrv('', {server:true, port:8080, pageStr:'Goodbye, World!'});
...other terminal...
prompt$ curl http://localhost:8080/page
Goodbye, World!prompt$ curl http://localhost:8080/page
Goodbye, World! |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Julia | Julia | using HttpServer
server = Server() do req, res
"Goodbye, World!"
end
run(server, 8080)
|
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #PowerShell | PowerShell |
$XMLdata=@"
<?xml version="1.0" encoding="utf-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
<servicing>
<package action="configure">
<assemblyIdentity name="Microsoft-Windows-Foundation-Package" version="${strFullVersion}" processorArchitecture="amd64" publicKeyToken="31bf3856ad36... |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Python | Python | print("""\
Usage: thingy [OPTIONS]
-h Display this usage message
-H hostname Hostname to connect to
""") |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Racket | Racket |
#lang racket/base
(displayln #<<EOF
Blah blah blah
with indentation intact
and "free" \punctuations\
EOF
)
|
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Raku | Raku | my $color = 'green';
say qq :to 'END';
some line
color: $color
another line
END |
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #Swift | Swift | var historyOfHistory = [Int]()
var history:Int = 0 {
willSet {
historyOfHistory.append(history)
}
}
history = 2
history = 3
history = 4
println(historyOfHistory)
|
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #Tcl | Tcl | # Define the history machinery
proc histvar {varName operation} {
upvar 1 $varName v ___history($varName) history
switch -- $operation {
start {
set history {}
if {[info exist v]} {
lappend history $v
}
trace add variable v write [list histvar.write $varName]
trace add variable v rea... |
http://rosettacode.org/wiki/Hofstadter_Figure-Figure_sequences | Hofstadter Figure-Figure sequences | These two sequences of positive integers are defined as:
R
(
1
)
=
1
;
S
(
1
)
=
2
R
(
n
)
=
R
(
n
−
1
)
+
S
(
n
−
1
)
,
n
>
1.
{\displaystyle {\begin{aligned}R(1)&=1\ ;\ S(1)=2\\R(n)&=R(n-1)+S(n-1),\quad n>1.\end{aligned}}}
The sequence
S
(
n
)
{\displaystyle S(n)}
is further... | #PicoLisp | PicoLisp | (setq *RNext 2)
(de ffr (N)
(cache '(NIL) N
(if (= 1 N)
1
(+ (ffr (dec N)) (ffs (dec N))) ) ) )
(de ffs (N)
(cache '(NIL) N
(if (= 1 N)
2
(let S (inc (ffs (dec N)))
(when (= S (ffr *RNext))
(inc 'S)
(inc '*RNext) )
... |
http://rosettacode.org/wiki/Hofstadter_Figure-Figure_sequences | Hofstadter Figure-Figure sequences | These two sequences of positive integers are defined as:
R
(
1
)
=
1
;
S
(
1
)
=
2
R
(
n
)
=
R
(
n
−
1
)
+
S
(
n
−
1
)
,
n
>
1.
{\displaystyle {\begin{aligned}R(1)&=1\ ;\ S(1)=2\\R(n)&=R(n-1)+S(n-1),\quad n>1.\end{aligned}}}
The sequence
S
(
n
)
{\displaystyle S(n)}
is further... | #PL.2FI | PL/I | ffr: procedure (n) returns (fixed binary(31));
declare n fixed binary (31);
declare v(2*n+1) bit(1);
declare (i, j) fixed binary (31);
declare (r, s) fixed binary (31);
v = '0'b;
v(1) = '1'b;
if n = 1 then return (1);
r = 1;
do i = 2 to n;
do j = 2 to 2*n;
if v(j) = '0'b ... |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Objeck | Objeck |
class Horner {
function : Main(args : String[]) ~ Nil {
coeffs := Collection.FloatVector->New();
coeffs->AddBack(-19.0);
coeffs->AddBack(7.0);
coeffs->AddBack(-4.0);
coeffs->AddBack(6.0);
PolyEval(coeffs, 3)->PrintLine();
}
function : PolyEval(coefficients : Collection.FloatVector , ... |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Objective-C | Objective-C | #import <Foundation/Foundation.h>
typedef double (^mfunc)(double, double);
@interface NSArray (HornerRule)
- (double)horner: (double)x;
- (NSArray *)reversedArray;
- (double)injectDouble: (double)s with: (mfunc)op;
@end
@implementation NSArray (HornerRule)
- (NSArray *)reversedArray
{
return [[self reverseObjec... |
http://rosettacode.org/wiki/Hilbert_curve | Hilbert curve |
Task
Produce a graphical or ASCII-art representation of a Hilbert curve of at least order 3.
| #Python | Python | '''Hilbert curve'''
from itertools import (chain, islice)
# hilbertCurve :: Int -> SVG String
def hilbertCurve(n):
'''An SVG string representing a
Hilbert curve of degree n.
'''
w = 1024
return svgFromPoints(w)(
hilbertPoints(w)(
hilbertTree(n)
)
)
# hilb... |
http://rosettacode.org/wiki/Holidays_related_to_Easter | Holidays related to Easter | Task
Calculate the dates of:
Easter
Ascension Thursday
Pentecost
Trinity Sunday
Corpus Christi feast (for Catholic)
All Saints' Sunday (for Orthodox)
As an example, calculate for the first year of each century from;
years 400 to 2100 CE and for
years 2010 to 2020 CE.
Note
... | #Maxima | Maxima | /* Easter sunday. Result is a list [month, day]
See:
Jean Meeus, "Astronomical Formulae for Calculators",
4th edition, Willmann-Bell, 1988, p.31 */
easter_sunday(year):=block([a,b,c,d,e,f,g,h,i,k,l,m,n,p],
a:remainder(year,19),[b,c]:divide(year,100),[d,e]:divide(b,4),
f:quotient(b+8,25),g:quotient(b-f+1,3),h:remain... |
http://rosettacode.org/wiki/Horizontal_sundial_calculations | Horizontal sundial calculations | Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island, aka Ernest Legouve Reef), wit... | #OoRexx | OoRexx | /*REXX pgm shows: hour, sun hour angle, dial hour line angle, 6am ---> 6pm*/
/* Use trigonometric functions provided by rxCalc */
parse arg lat lng mer . /*get the optional arguments from the CL*/
/*None specified? Then use the default of Jules ... |
http://rosettacode.org/wiki/Huffman_coding | Huffman coding | Huffman encoding is a way to assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.
For example, if you use letters as symbols and have details of the frequency of occurrence of those letters in typical strings, then you could just encode each letter wi... | #PureBasic | PureBasic |
OpenConsole()
SampleString.s="this is an example for huffman encoding"
datalen=Len(SampleString)
Structure ztree
linked.c
ischar.c
char.c
number.l
left.l
right.l
EndStructure
Dim memc.c(datalen)
CopyMemory(@SampleString, @memc(0), datalen * SizeOf(Character))
Dim tree.ztree(255)
For i=0 To datal... |
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #Smalltalk | Smalltalk | (Array2D identity: (UIManager default request: 'Enter size of the matrix:') asInteger) asString |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #SNUSP | SNUSP | ++++>++++ a b !/?\<?\# a=b
> - \# a>b
- <
a<b #\?/ |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #Sparkling | Sparkling | let a = 13, b = 37;
if a < b {
print("a < b");
} else if a > b {
print("a > b");
} else if a == b {
print("a == b");
} else {
print("either a or b or both are NaN");
} |
http://rosettacode.org/wiki/HTTP | HTTP | Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| #Java | Java | import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.Charset;
public class Main {
public static void main(String[] args) {
var request = HttpRequest.newBuilder(URI.create("https://www.rosettacode.org"))
... |
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #Nim | Nim | import strutils
const last = 1 shl 20
var aList: array[last + 1, int]
aList[0..2] = [-50_000, 1, 1]
var
v = aList[2]
k1 = 2
lg2 = 1
aMax = 0.0
for n in 3..last:
v = aList[v] + aList[n-v]
aList[n] = v
aMax = max(aMax, v.float / n.float)
if (k1 and n) == 0:
echo "Maximum between 2^$# and 2... |
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #Objeck | Objeck | bundle Default {
class HofCon {
function : Main(args : String[]) ~ Nil {
DoSqnc(1<<20);
}
function : native : DoSqnc(m : Int) ~ Nil {
a_list := Int->New[m + 1];
max_df := 0;
p2_max := 2;
k1 := 2;
lg2 := 1;
amax := 0.0;
a_list[0] := 1;
a_list[1] :... |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #J | J | stderr =: 1!:2&4
stderr 'Goodbye, World!' |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #Java | Java | public class Err{
public static void main(String[] args){
System.err.println("Goodbye, World!");
}
} |
http://rosettacode.org/wiki/Hello_world/Standard_error | Hello world/Standard error | Hello world/Standard error is part of Short Circuit's Console Program Basics selection.
A common practice in computing is to send error messages
to a different output stream than normal text console messages.
The normal messages print to what is called "standard output" or "standard out".
The error messages print to ... | #JavaScript | JavaScript | WScript.StdErr.WriteLine("Goodbye, World!"); |
http://rosettacode.org/wiki/Hofstadter_Q_sequence | Hofstadter Q sequence | Hofstadter Q sequence
Q
(
1
)
=
Q
(
2
)
=
1
,
Q
(
n
)
=
Q
(
n
−
Q
(
n
−
1
)
)
+
Q
(
n
−
Q
(
n
−
2
)
)
,
n
>
2.
{\displaystyle {\begin{aligned}Q(1)&=Q(2)=1,\\Q(n)&=Q{\big (}n-Q(n-1){\big )}+Q{\big (}n-Q(n-2){\big )},\quad n>2.\end{aligned}}}
It is defined like the Fibonacc... | #FreeBASIC | FreeBASIC |
Const limite = 100000
Dim As Long Q(limite), i, cont = 0
Q(1) = 1
Q(2) = 1
For i = 3 To limite
Q(i) = Q(i-Q(i-1)) + Q(i-Q(i-2))
If Q(i) < Q(i-1) Then cont += 1
Next i
Print "Primeros 10 terminos: ";
For i = 1 To 10
Print Q(i) &" ";
Next i
Print
Print "Termino numero 1000: "; Q(1000)
Print "Ter... |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Seed7 | Seed7 | $ include "seed7_05.s7i";
include "bigrat.s7i";
const proc: main is func
local
const bigRational: ln2 is 6931471805599453094172_ / 10000000000000000000000_;
var bigRational: h is 1_ / 2_ / ln2;
var integer: n is 0;
var string: stri is "";
begin
for n range 1 to 17 do
h := h * bigRation... |
http://rosettacode.org/wiki/Hickerson_series_of_almost_integers | Hickerson series of almost integers | The following function, due to D. Hickerson, is said to generate "Almost integers" by the
"Almost Integer" page of Wolfram MathWorld, (December 31 2013). (See formula numbered 51.)
The function is:
h
(
n
)
=
n
!
2
(
ln
2
)
n
+
1
{\displaystyle h(n)={\operatorname {n} ! \ove... | #Sidef | Sidef | func h(n) {
n! / (2 * pow(2.log, n+1))
}
{ |n|
"h(%2d) = %22s is%s almost an integer.\n".printf(
n, var hn = h(n).round(-3), hn.to_s ~~ /\.[09]/ ? '' : ' NOT')
} << 1..17 |
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
| #ACL2 | ACL2 | (cw "Hello world!~%") |
http://rosettacode.org/wiki/Heronian_triangles | Heronian triangles | Hero's formula for the area of a triangle given the length of its three sides a, b, and c is given by:
A
=
s
(
s
−
a
)
(
s
−
b
)
(
s
−
c
)
,
{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}},}
where s is half the perimeter of the triangle; that is,
s
=
a
+
b
+
c
2
.
{\displaystyle s... | #Haskell | Haskell | import qualified Data.List as L
import Data.Maybe
import Data.Ord
import Text.Printf
-- Determine if a number n is a perfect square and return its square root if so.
-- This is used instead of sqrt to avoid fixed sized floating point numbers.
perfectSqrt :: Integral a => a -> Maybe a
perfectSqrt n
| n == 1 = Jus... |
http://rosettacode.org/wiki/Higher-order_functions | Higher-order functions | Task
Pass a function as an argument to another function.
Related task
First-class functions
| #C.23 | C# | f=Add, f(6, 2) = 8
f=Mul, f(6, 2) = 12
f=Div, f(6, 2) = 3
|
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Kotlin | Kotlin | import java.io.PrintWriter
import java.net.ServerSocket
fun main(args: Array<String>) {
val listener = ServerSocket(8080)
while(true) {
val sock = listener.accept()
PrintWriter(sock.outputStream, true).println("Goodbye, World!")
sock.close()
}
} |
http://rosettacode.org/wiki/Hello_world/Web_server | Hello world/Web server | The browser is the new GUI !
Task
Serve our standard text Goodbye, World! to http://localhost:8080/ so that it can be viewed with a web browser.
The provided solution must start or implement a server that accepts multiple client connections and serves text as requested.
Note that starting a web browser or... | #Lasso | Lasso | local(server) = net_tcp
handle => { #server->close }
#server->bind(8080) & listen & forEachAccept => {
local(con) = #1
split_thread => {
handle => { #con->close }
local(request) = ''
// Read in the request in chunks until you have it all
{
#request->append(#con->readSomeBytes(80... |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Raven | Raven | 'Buffy the Vampire Slayer' as sender
'Spike' as recipient
[
"Dear %(recipient)s,
"
"I wish you to leave Sunnydale and never return.
"
"Not Quite Love,
"%(sender)s
] "\n" join print
|
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #REXX | REXX | /*REXX program demonstrates a method to use "here" documents in REXX. */
parse arg doc . /*"here" name is case sensitive. */
do j=1 for sourceline()
if sourceline(j)\=='◄◄'doc then iterate
do !=j+1 to sourceline() while sourceline(!)\=='◄◄.'
say sourceline(... |
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Ring | Ring |
text ="
<<'FOO'
Now
is
the
time
for
all
good mem
to come to the aid of their country."
see text + nl
|
http://rosettacode.org/wiki/Here_document | Here document | A here document (or "heredoc") is a way of specifying a text block, preserving the line breaks, indentation and other whitespace within the text.
Depending on the language being used, a here document is constructed using a command followed by "<<" (or some other symbol) followed by a token string.
The text ... | #Ruby | Ruby | address = <<END
1, High Street,
#{town_name},
West Midlands.
WM4 5HD.
END |
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #Wren | Wren | class HistoryVariable {
construct new(initValue) {
_history = [initValue]
}
currentValue { _history[-1] }
currentValue=(newValue) { _history.add(newValue) }
showHistory() {
System.print("The variable's history, oldest values first, is:")
for (item in _history) System.prin... |
http://rosettacode.org/wiki/History_variables | History variables | Storing the history of objects in a program is a common task.
Maintaining the history of an object in a program has traditionally required programmers either to write specific code for handling the historical data, or to use a library which supports history logging.
History variables are variables in a programming la... | #zkl | zkl | class HistoryVar{
var [private] _v, _history=List(), maxSz;
fcn init(v,maxEntries=3){ maxSz=maxEntries; set(v) }
fcn set(v){
_v=v; _history.append(T(Time.Clock.time,v));
if(_history.len()>maxSz) _history.del(0);
self
}
fcn get(n=0){ // look back into history
z:=_history.len();
... |
http://rosettacode.org/wiki/Hofstadter_Figure-Figure_sequences | Hofstadter Figure-Figure sequences | These two sequences of positive integers are defined as:
R
(
1
)
=
1
;
S
(
1
)
=
2
R
(
n
)
=
R
(
n
−
1
)
+
S
(
n
−
1
)
,
n
>
1.
{\displaystyle {\begin{aligned}R(1)&=1\ ;\ S(1)=2\\R(n)&=R(n-1)+S(n-1),\quad n>1.\end{aligned}}}
The sequence
S
(
n
)
{\displaystyle S(n)}
is further... | #Prolog | Prolog | :- use_module(library(chr)).
:- chr_constraint ffr/2, ffs/2, hofstadter/1,hofstadter/2.
:- chr_option(debug, off).
:- chr_option(optimize, full).
% to remove duplicates
ffr(N, R1) \ ffr(N, R2) <=> R1 = R2 | true.
ffs(N, R1) \ ffs(N, R2) <=> R1 = R2 | true.
% compute ffr
ffr(N, R), ffr(N1, R1), ffs(N1,S1) ==>
... |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #OCaml | OCaml | # let horner coeffs x =
List.fold_left (fun acc coef -> acc * x + coef) 0 (List.rev coeffs) ;;
val horner : int list -> int -> int = <fun>
# let coeffs = [-19; 7; -4; 6] in
horner coeffs 3 ;;
- : int = 128 |
http://rosettacode.org/wiki/Horner%27s_rule_for_polynomial_evaluation | Horner's rule for polynomial evaluation | A fast scheme for evaluating a polynomial such as:
−
19
+
7
x
−
4
x
2
+
6
x
3
{\displaystyle -19+7x-4x^{2}+6x^{3}\,}
when
x
=
3
{\displaystyle x=3\;}
.
is to arrange the computation as follows:
(
(
(
(
0
)
x
+
6
)
x
+
(
−
4
)
)
x
+
7
)
x
+
(
−
19
)
{\displaystyle ((((0)x+6)x+(-4))x... | #Octave | Octave | function r = horner(a, x)
r = 0.0;
for i = length(a):-1:1
r = r*x + a(i);
endfor
endfunction
horner([-19, 7, -4, 6], 3) |
http://rosettacode.org/wiki/Hilbert_curve | Hilbert curve |
Task
Produce a graphical or ASCII-art representation of a Hilbert curve of at least order 3.
| #QB64 | QB64 | _Title "Hilbert Curve"
Dim Shared As Integer sw, sh, wide, cell
wide = 128: cell = 4
sw = wide * cell + cell
sh = sw
Screen _NewImage(sw, sh, 8)
Cls , 15: Color 0
PSet (wide * cell, wide * cell)
Call Hilbert(0, 0, wide, 0, 0)
Sleep
System
Sub Hilbert (x As Integer, y As Integer, lg As Integer, p As Integer, q... |
http://rosettacode.org/wiki/Hilbert_curve | Hilbert curve |
Task
Produce a graphical or ASCII-art representation of a Hilbert curve of at least order 3.
| #Quackery | Quackery | [ $ "turtleduck.qky" loadfile ] now!
[ stack ] is switch.arg ( --> [ )
[ switch.arg put ] is switch ( x --> )
[ switch.arg release ] is otherwise ( --> )
[ switch.arg share
!= iff ]else[ done
otherwise ]'[ do ]done[ ] is case ( ... |
http://rosettacode.org/wiki/Holidays_related_to_Easter | Holidays related to Easter | Task
Calculate the dates of:
Easter
Ascension Thursday
Pentecost
Trinity Sunday
Corpus Christi feast (for Catholic)
All Saints' Sunday (for Orthodox)
As an example, calculate for the first year of each century from;
years 400 to 2100 CE and for
years 2010 to 2020 CE.
Note
... | #.D0.9C.D0.9A-61.2F52 | МК-61/52 | П2 1 9 ПП 86 П3 ИП2 4 ПП 86
П4 ИП2 7 ПП 86 П5 1 9 ИП3 *
1 5 + 3 0 ПП 86 П6 2 ИП4
* 4 ИП5 * + 6 ИП6 * + 6
+ 7 ПП 86 ИП6 + П1 3 П4 ИП2
1 - 2 10^x / [x] ^ ^ 4 /
[x] - 2 0 + ИП1 + П3 3 1
- x>=0 76 П3 КИП4 ИП3 3 0 - x>=0
83 П3 КИП4 ИП3 ИП4 С/П П0 <-> П1 <->
/ [x] ИП0 * ИП1 - /-/ В/О |
http://rosettacode.org/wiki/Horizontal_sundial_calculations | Horizontal sundial calculations | Task
Create a program that calculates the hour, sun hour angle, dial hour line angle from 6am to 6pm for an operator entered location.
For example, the user is prompted for a location and inputs the latitude and longitude 4°57′S 150°30′W (4.95°S 150.5°W of Jules Verne's Lincoln Island, aka Ernest Legouve Reef), wit... | #Pascal | Pascal | Program SunDial;
Const
pi = 3.14159265358979323846;
dr = pi/180.0;
rd = 180.0/pi;
tab = chr(9);
Var
lat, slat, lng, ref : Real;
hla, hra : Real;
h : Integer;
function tan(val : Real) : Real;
begin
tan := sin(val)/cos(val)
end;
Begin
Write('Enter latitude: '); Read(l... |
http://rosettacode.org/wiki/Huffman_coding | Huffman coding | Huffman encoding is a way to assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.
For example, if you use letters as symbols and have details of the frequency of occurrence of those letters in typical strings, then you could just encode each letter wi... | #Python | Python | from heapq import heappush, heappop, heapify
from collections import defaultdict
def encode(symb2freq):
"""Huffman encode the given dict mapping symbols to weights"""
heap = [[wt, [sym, ""]] for sym, wt in symb2freq.items()]
heapify(heap)
while len(heap) > 1:
lo = heappop(heap)
hi = he... |
http://rosettacode.org/wiki/Identity_matrix | Identity matrix | Task
Build an identity matrix of a size known at run-time.
An identity matrix is a square matrix of size n × n,
where the diagonal elements are all 1s (ones),
and all the other elements are all 0s (zeroes).
I
n
=
[
1
0
0
⋯
0
0
1
0
⋯
0
0
0
1
⋯
0
⋮
⋮
⋮
⋱
... | #Sparkling | Sparkling | function unitMatrix(n) {
return map(range(n), function(k1, v1) {
return map(range(n), function(k2, v2) {
return v2 == v1 ? 1 : 0;
});
});
} |
http://rosettacode.org/wiki/Integer_comparison | Integer comparison |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |... | #SQL | SQL |
DROP TABLE test;
CREATE TABLE test(a INTEGER, b INTEGER);
INSERT INTO test VALUES (1,2);
INSERT INTO test VALUES (2,2);
INSERT INTO test VALUES (2,1);
SELECT to_char(a)||' is less than '||to_char(b) less_than
FROM test
WHERE a < b;
SELECT to_char(a)||' is equal to '||to_char(b) equal_to
FROM test
WHERE a ... |
http://rosettacode.org/wiki/HTTP | HTTP | Task
Access and print a URL's content (the located resource) to the console.
There is a separate task for HTTPS Requests.
| #JavaScript | JavaScript | var req = new XMLHttpRequest();
req.onload = function() {
console.log(this.responseText);
};
req.open('get', 'http://rosettacode.org', true);
req.send() |
http://rosettacode.org/wiki/Hofstadter-Conway_$10,000_sequence | Hofstadter-Conway $10,000 sequence | The definition of the sequence is colloquially described as:
Starting with the list [1,1],
Take the last number in the list so far: 1, I'll call it x.
Count forward x places from the beginning of the list to find the first number to add (1)
Count backward x places from the end of the list to find the secon... | #Oforth | Oforth | : hofstadter(n)
| l i |
ListBuffer newSize(n) dup add(1) dup add(1) ->l
n 2 - loop: i [ l at(l last) l at(l size l last - 1+ ) + l add ]
l dup freeze ;
: hofTask
| h m i |
2 20 pow ->m
hofstadter(m) m seq zipWith(#[ tuck asFloat / swap Pair new ]) ->h
19 loop: i [
i . "^2 ==>" .
h ext... |
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