Create a two-dimensional array at runtime

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Task
Create a two-dimensional array at runtime
You are encouraged to solve this task according to the task description, using any language you may know.

Data Structure
This illustrates a data structure, a means of storing data within a program.

You may see other such structures in the Data Structures category.

Get two integers from the user, then create a two-dimensional array where the two dimensions have the sizes given by those numbers, and which can be accessed in the most natural way possible. Write some element of that array, and then output that element. Finally destroy the array if not done by the language itself.

Contents

[edit] Ada

 
with Ada.Text_Io;
with Ada.Float_Text_Io;
with Ada.Integer_Text_Io;
 
procedure Two_Dimensional_Arrays is
type Matrix_Type is array(Positive range <>, Positive range <>) of Float;
Dim_1 : Positive;
Dim_2 : Positive;
begin
Ada.Integer_Text_Io.Get(Item => Dim_1);
Ada.Integer_Text_Io.Get(Item => Dim_2);
-- Create an inner block with the correctly sized array
declare
Matrix : Matrix_Type(1..Dim_1, 1..Dim_2);
begin
Matrix(1, Dim_2) := 3.14159;
Ada.Float_Text_Io.Put(Item => Matrix(1, Dim_2), Fore => 1, Aft => 5, Exp => 0);
Ada.Text_Io.New_Line;
end;
-- The variable Matrix is popped off the stack automatically
end Two_Dimensional_Arrays;

[edit] ALGOL 68

main:(
print("Input two positive whole numbers separated by space and press newline:");
[read int,read int] INT array;
array[1,1]:=42;
print (array[1,1])
)

[edit] APL

Arrays are an integral part of APL. Array size, shape, and data type can be easily manipulated at runtime.

array←m n ⍴ 0 ⍝ array of zeros with shape of m by n.
 
array[1;1]←73 ⍝ assign a value to location 1;1.
 
array[1;1] ⍝ read the value back out
 
⎕ex 'array' ⍝ erase the array
 

[edit] AppleScript

AppleScript has no array, but an AppleScript list can be used in a multidimensional fashion. There's no issue with their dimensions, they grow while adding elements. Memory allocation is dynamic.

set R to text returned of (display dialog "Enter number of rows:" default answer 2) as integer
set c to text returned of (display dialog "Enter number of columns:" default answer 2) as integer
set array to {}
repeat with i from 1 to R
set temp to {}
repeat with j from 1 to c
set temp's end to 0
end repeat
set array's end to temp
end repeat
 
-- Address the first column of the first row:
set array's item 1's item 1 to -10
 
-- Negative index values can be used to address from the end:
set array's item -1's item -1 to 10
 
-- Access an item (row 2 column 1):
set x to array's item 2's item 1
 
return array
 
-- Destroy array (typically unnecessary since it'll automatically be destroyed once script ends).
set array to {}
 

[edit] AutoHotkey

Works with: AutoHotkey_L
Array := []
InputBox, data,, Enter two integers separated by a Space:`n(ex. 5 7)
StringSplit, i, data, %A_Space%
Array[i1,i2] := "that element"
MsgBox, % "Array[" i1 "," i2 "] = " Array[i1,i2]

[edit] AutoIt

; == get dimensions from user input
$sInput = InputBox('2D Array Creation', 'Input comma separated count of rows and columns, i.e. "5,3"')
$aDimension = StringSplit($sInput, ',', 2)
 
; == create array
Dim $a2D[ $aDimension[0] ][ $aDimension[1] ]
 
; == write value to last row/last column
$a2D[ UBound($a2D) -1 ][ UBound($a2D, 2) -1 ] = 'test string'
 
; == output this value to MsgBox
MsgBox(0, 'Output', 'row[' & UBound($a2D) -1 & '], col[' & UBound($a2D, 2) -1 & ']' & @CRLF & '= ' & $a2D[ UBound($a2D) -1 ][ UBound($a2D, 2) -1 ] )
 
 

[edit] AWK

AWK has no multidimensional array; but AWK arrays (which are Associative array indeed) can be used also in a multidimensional fashion. Since AWK arrays are associative arrays, there's no issue in their dimensions: they grow while adding new key-value pair.

/[0-9]+ [0-9]+/ {
for(i=0; i < $1; i++) {
for(j=0; j < $2; j++) {
arr[i, j] = i*j
}
}
 
# how to scan "multidim" array as explained in the GNU AWK manual
for (comb in arr) {
split(comb, idx, SUBSEP)
print idx[1] "," idx[2] "->" arr[idx[1], idx[2]]
}
}

[edit] BASIC

Works with: QuickBasic version 4.5
CLS
INPUT a, b 'inputs need to be separated by commas
DIM array (1 TO a, 1 TO b)
array(1,1) = 42
PRINT array(1,1)
ERASE array

[edit] BBC BASIC

      INPUT "Enter array dimensions separated by a comma: " a%, b%
 
DIM array(a%, b%)
array(1, 1) = PI
PRINT array(1, 1)

[edit] C

[edit] C99

Works with: C99
#include <stdio.h>
 
int main(int argc, char **argv) {
 
int user1 = 0, user2 = 0;
printf("Enter two integers. Space delimited, please: ");
scanf("%d %d",&user1, &user2);
int array[user1][user2];
array[user1/2][user2/2] = user1 + user2;
printf("array[%d][%d] is %d\n",user1/2,user2/2,array[user1/2][user2/2]);
 
return 0;
}

[edit] Traditional Style

This style is supported by all 'C' compilers.

#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
int user1 = 0, user2 = 0;
int *a1, **array, row;
 
printf("Enter two integers. Space delimited, please: ");
scanf("%d %d",&user1, &user2);
 
a1 = malloc(user1*user2*sizeof(int));
array = malloc(user1*sizeof(int*));
for (row=0; row<user1; row++) array[row]=a1+row*user2;
 
array[user1/2][user2/2] = user1 + user2;
printf("array[%d][%d] is %d\n",user1/2,user2/2,array[user1/2][user2/2]);
free(array);
free(a1);
return 0;
}

This style also supports more efficient memory utilization if you're only using a portion of the array. If you only need the upper right half of a square array, you can do something like the following.

#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
int user1 = 0;
int space_needed;
int *a1, **array;
int row, col, offset;
 
printf("Enter size of array: ");
scanf("%d",&user1);
 
space_needed = (user1+1)*user1/2;
a1 = malloc(space_needed * sizeof(*a1));
array = malloc(user1 * sizeof(*array));
for (row=0,offset=0; row<user1; offset+=(user1-row), row++) {
array[row]=a1+offset-row;
for (col=row; col<user1; col++)
array[row][col] = 1+col-row;
}
for (row=0; row<user1; row++)
printf("%d ", array[row][user1-1]);
printf("\n");
 
free(array);
free(a1);
return 0;
}

This approach most closely matches the C99 example, as alloca allocates on the stack, rather than the heap, as malloc does.

#include <stdio.h>
#include <alloca.h>
int main(int argc, char **argv)
{
int user1 = 0, user2 = 0;
int *a1, **array, row;
 
printf("Enter two integers. Space delimited, please: ");
scanf("%d %d",&user1, &user2);
 
a1 = alloca(user1*user2*sizeof(int));
array = alloca(user1*sizeof(int*));
for (row=0; row<user1; row++) array[row]=a1+row*user2;
 
array[user1/2][user2/2] = user1 + user2;
printf("array[%d][%d] is %d\n",user1/2,user2/2,array[user1/2][user2/2]);
return 0;
}

[edit] C++

With language built-in facilities:

#include <iostream>
#include <istream>
#include <ostream>
 
int main()
{
// read values
int dim1, dim2;
std::cin >> dim1 >> dim2;
 
// create array
double* array_data = new double[dim1*dim2];
double** array = new double*[dim1];
for (int i = 0; i < dim1; ++i)
array[i] = array_data + dim2*i;
 
// write element
array[0][0] = 3.5;
 
// output element
std::cout << array[0][0] << std::endl;
 
// get rid of array
delete[] array;
delete[] array_data;
}

Using std::vector from the standard library:

#include <iostream>
#include <istream>
#include <ostream>
#include <vector>
 
int main()
{
// read values
int dim1, dim2;
std::cin >> dim1 >> dim2;
 
// create array
std::vector<std::vector<double> > array(dim1, std::vector<double>(dim2));
 
// write element
array[0][0] = 3.5;
 
// output element
std::cout << array[0][0] << std::endl;
 
// the array is automatically freed at the end of main()
}

Using boost::multi_array.

Library: Boost
#include <iostream>
#include "boost/multi_array.hpp"
 
typedef boost::multi_array<double, 2> two_d_array_type;
 
int main()
{
// read values
int dim1, dim2;
std::cin >> dim1 >> dim2;
 
// create array
two_d_array_type A(boost::extents[dim1][dim2]);
 
// write elements
A[0][0] = 3.1415;
 
// read elements
std::cout << A[0][0] << std::endl;
}
 

[edit] C#

 
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter two integers. Space delimited please: ");
string s = Console.ReadLine();
 
int[,] myArray=new int[(int)s[0],(int)s[2]];
myArray[0, 0] = 2;
Console.WriteLine(myArray[0, 0]);
 
Console.ReadLine();
}
}
 

[edit] Clean

import StdEnv
 
Start :: *World -> { {Real} }
Start world
# (console, world) = stdio world
(_, dim1, console) = freadi console
(_, dim2, console) = freadi console
= createArray dim1 (createArray dim2 1.0)


[edit] Clojure

(let [rows (Integer/parseInt (read-line))
cols (Integer/parseInt (read-line))
a (to-array-2d (repeat rows (repeat cols nil)))]
(aset a 0 0 12)
(println "Element at 0,0:" (aget a 0 0)))

[edit] Common Lisp

(let ((d1 (read))
(d2 (read)))
(assert (and (typep d1 '(integer 1))
(typep d2 '(integer 1)))
(d1 d2))
(let ((array (make-array (list d1 d2) :initial-element nil))
(p1 0)
(p2 (floor d2 2)))
(setf (aref array p1 p2) t)
(print (aref array p1 p2))))

The assert will allow the user to reenter the dimensions if they are not positive integers.

[edit] Component Pascal

Arrays in Component Pascal are started from zero index. No DISPOSE-like procedures because of garbage collection.

 
MODULE TestArray;
(* Implemented in BlackBox Component Builder *)
 
IMPORT Out;
 
(* Open array *)
 
PROCEDURE DoTwoDim*;
VAR d: POINTER TO ARRAY OF ARRAY OF INTEGER;
BEGIN
NEW(d, 5, 4); (* allocating array in memory *)
d[1, 2] := 100; (* second row, third column element *)
d[4, 3] := -100; (* fifth row, fourth column element *)
Out.Int(d[1, 2], 0); Out.Ln;
Out.Int(d[4, 3], 0); Out.Ln;
END DoTwoDim;
 
END TestArray.

[edit] D

void main() {
import std.stdio, std.conv, std.string;
int nRow, nCol;
 
write("Give me the numer of rows: ");
try {
nRow = readln.strip.to!int;
} catch (StdioException) {
nRow = 3;
writeln;
}
 
write("Give me the numer of columns: ");
try {
nCol = readln.strip.to!int;
} catch (StdioException) {
nCol = 5;
writeln;
}
 
auto array = new float[][](nRow, nCol);
array[0][0] = 3.5;
writeln("The number at place [0, 0] is ", array[0][0]);
}
Output:
Give me the numer of rows: 
Give me the numer of columns: 
The number at place [0, 0] is 3.5

[edit] Delphi

Dimensions are generated randomly, not input by user.

program Project1;
 
{$APPTYPE CONSOLE}
 
uses
SysUtils;
var
matrix:array of array of Byte;
i,j:Integer;
begin
Randomize;
//Finalization is not required in this case, but you have to do
//so when reusing the variable in scope
Finalize(matrix);
//Init first dimension with random size from 1..10
//Remember dynamic arrays are indexed from 0
SetLength(matrix,Random(10) + 1);
//Init 2nd dimension with random sizes too
for i := Low(matrix) to High(matrix) do
SetLength(matrix[i],Random(10) + 1);
 
//End of code, the following part is just output
Writeln(Format('Total amount of columns = %.2d',[Length(matrix)]));
for i := Low(matrix) to High(matrix) do
Writeln(Format('Column %.2d = %.2d rows',[i,Length(matrix[i])]));
 
Readln;
end.
 

Test run:

Total amount of columns = 10
Column 00 = 04 rows
Column 01 = 08 rows
Column 02 = 09 rows
Column 03 = 05 rows
Column 04 = 01 rows
Column 05 = 04 rows
Column 06 = 07 rows
Column 07 = 04 rows
Column 08 = 10 rows
Column 09 = 02 rows


[edit] Erlang

 
-module( two_dimensional_array ).
 
-export( [create/2, get/3, set/4, task/0] ).
 
create( X, Y ) -> array:new( [{size, X}, {default, array:new( [{size, Y}] )}] ).
 
get( X, Y, Array ) -> array:get( Y, array:get(X, Array) ).
 
set( X, Y, Value, Array ) ->
Y_array = array:get( X, Array ),
New_y_array = array:set( Y, Value, Y_array ),
array:set( X, New_y_array, Array ).
 
task() ->
{ok, [X, Y]} = io:fread( "Input two integers. Space delimited, please: ", "~d ~d" ),
Array = create( X, Y ),
New_array = set( X - 1, Y - 1, X * Y, Array ),
io:fwrite( "In position ~p ~p we have ~p~n", [X - 1, Y - 1, get( X - 1, Y - 1, New_array)] ).
 
Output:
7> two_dimensional_array:task().
Input two integers.  Space delimited, please:  4 5
In position 3 4 we have 20

[edit] Euphoria

include get.e
 
sequence array
integer height,width,i,j
 
height = floor(prompt_number("Enter height: ",{}))
width = floor(prompt_number("Enter width: ",{}))
 
array = repeat(repeat(0,width),height)
 
i = floor(height/2+0.5)
j = floor(width/2+0.5)
array[i][j] = height + width
 
printf(1,"array[%d][%d] is %d\n", {i,j,array[i][j]})

[edit] Factor

Factor doesn't provide any support for easy access of 2d arrays. But since factor's written in factor, we can just add it and it's just as good :)

USING: io kernel math.matrices math.parser prettyprint
sequences ;
IN: rosettacode.runtime2darray
 
: set-Mi,j ( elt {i,j} matrix -- )
[ first2 swap ] dip nth set-nth ;
: Mi,j ( {i,j} matrix -- elt )
[ first2 swap ] dip nth nth ;
 
: example ( -- )
readln readln [ string>number ] bi@ zero-matrix ! create the array
[ [ 42 { 0 0 } ] dip set-Mi,j ] ! set the { 0 0 } element to 42
[ [ { 0 0 } ] dip Mi,j . ] ! read the { 0 0 } element
bi ;

[edit] Forth

: cell-matrix
create ( width height "name" ) over , * cells allot
does> ( x y -- addr ) dup cell+ >r @ * + cells r> + ;
 
5 5 cell-matrix test
 
36 0 0 test !
0 0 test @ . \ 36
INTEGER DMATRIX my-matrix{{
& my-matrix{{ 8 9 }}malloc
 
8 my-matrix{{ 3 4 }} !
my-matrix{{ 3 4 }} @ .
 
& my-matrix{{ }}free

[edit] Fortran

In Fortran 90 and later

PROGRAM Example
 
IMPLICIT NONE
INTEGER :: rows, columns, errcheck
INTEGER, ALLOCATABLE :: array(:,:)
 
WRITE(*,*) "Enter number of rows"
READ(*,*) rows
WRITE(*,*) "Enter number of columns"
READ(*,*) columns
 
ALLOCATE (array(rows,columns), STAT=errcheck) ! STAT is optional and is used for error checking
 
array(1,1) = 42
 
WRITE(*,*) array(1,1)
 
DEALLOCATE (array, STAT=errcheck)
 
END PROGRAM Example

[edit] Frink

 
[rows, cols] = dims = eval[input["Enter dimensions: ", ["Rows", "Columns"]]]
a = new array[dims, 0] // Create and initialize to 0
a@(rows-1)@(cols-1) = 10
println[a@(rows-1)@(cols-1)]
 

[edit] F#

open System
 
let width = int( Console.ReadLine() )
let height = int( Console.ReadLine() )
let arr = Array2D.create width height 0
arr.[0,0] <- 42
printfn "%d" arr.[0,0]

[edit] GAP

# Creating an array of 0
a := NullMat(2, 2);
# [ [ 0, 0 ], [ 0, 0 ] ]
 
# Some assignments
a[1][1] := 4;
a[1][2] := 5;
a[2][1] := 3;
a[2][2] := 4;
 
a
# [ [ 4, 5 ], [ 3, 4 ] ]
 
Determinant(a);
# 1

[edit] Go

Arrays in Go are only one dimensional. Code below show the obvious way of composing a 2d array as an array of arrays that can be indexed as a[r][c].

package main
 
import "fmt"
 
func main() {
var row, col int
fmt.Print("enter rows cols: ")
fmt.Scan(&row, &col)
 
// allocate composed 2d array
a := make([][]int, row)
for i := range a {
a[i] = make([]int, col)
}
 
// array elements initialized to 0
fmt.Println("a[0][0] =", a[0][0])
 
// assign
a[row-1][col-1] = 7
 
// retrieve
fmt.Printf("a[%d][%d] = %d\n", row-1, col-1, a[row-1][col-1])
 
// remove only reference
a = nil
// memory allocated earlier with make can now be garbage collected.
}

The technique above alocates each row separately. This might be good if you need extremely large arrays that cannot be allocated in a single piece. It might be bad though, for locality, as there would be no guarantee that the separate allocations would be localized in memory. A technique that maintains locality is this,

    // allocate composed 2d array
a := make([][]int, row)
e := make([]int, row * col)
for i := range a {
a[i] = e[i*col:(i+1)*col]
}

Now all rows are allocated with a single allocation. Alternatively, slice e can be used directly without going through slice a. Element r c can be accessed simply as e[r*cols+c] for example, or accessor functions can be defined such as,

 
func get(r, c int) int {
return e[r*cols+c]
}

[edit] Groovy

Solution:

def make2d = { nrows, ncols ->
(0..<nrows).collect { [0]*ncols }
}

Test:

def r = new Random()
 
System.in.splitEachLine(/,\s*/) { dim ->
def nrows = dim[0] as int
def ncols = dim[1] as int
 
def a2d = make2d(nrows, ncols)
 
def row = r.nextInt(nrows)
def col = r.nextInt(ncols)
def val = r.nextInt(nrows*ncols)
 
a2d[row][col] = val
 
println "a2d[${row}][${col}] == ${a2d[row][col]}"
 
a2d.each { println it }
println()
}

Input:

  3,   5
4, 4

Output:

a2d[0][3] == 8
[0, 0, 0, 8, 0]
[0, 0, 0, 0, 0]
[0, 0, 0, 0, 0]

a2d[2][2] == 5
[0, 0, 0, 0]
[0, 0, 0, 0]
[0, 0, 5, 0]
[0, 0, 0, 0]

[edit] Haskell

 doit n m = a!(0,0) where a = array ((0,0),(n,m)) [((0,0),42)]

[edit] HicEst

REAL :: array(1)
 
DLG(NameEdit=rows, NameEdit=cols, Button='OK', TItle='Enter array dimensions')
 
ALLOCATE(array, cols, rows)
array(1,1) = 1.234
WRITE(Messagebox, Name) array(1,1)

[edit] Icon and Unicon

All Icon and Unicon data objects are automatically reclaimed. Multiply dimensioned arrays are arrays of arrays in both languages.

procedure main(args)
nr := integer(args[1]) | 3 # Default to 3x3
nc := integer(args[2]) | 3
 
A := list(nr)
every !A := list(nc)
 
x := ?nr # Select a random element
y := ?nc
 
A[x][y] := &pi
write("A[",x,"][",y,"] -> ",A[x][y])
end

Sample output:

->ar 65 2
A[37][1] -> 3.141592654

[edit] IDL

The following is only for demonstration. No real program should just assume that the user input is valid, integer, large enough etc.

read, x, prompt='Enter x size:'
read, y, prompt='Enter y size:'
d = fltarr(x,y)
 
d[3,4] = 5.6
print,d[3,4]
;==> outputs 5.6
 
delvar, d

[edit] J

The natural ways of creating a two dimensional array, from array dimensions, in J are i. and $

   array1=:i. 3 4   NB. a 3 by 4 array with arbitrary values
array2=: 5 6 $ 2 NB. a 5 by 6 array where every value is the number 2

To update the upper left corner of the array with the value 99, you might use }

   array1=: 99 (<0 0)} array1

And, to retrieve that value you might use {

   (<0 0) { array1

Finally, J manages storage for you, so to delete the array, you could either have the name refer to a new value

   array1=: 0

or you could remove the name itself:

   erase'array1'

Putting these ideas together and adding a few frills:

task=: verb define
assert. y -: 0 0 + , y NB. error except when 2 dimensions are specified
INIT=. 0 NB. array will be populated with this value
NEW=. 1 NB. we will later update one location with this value
ARRAY=. y $ INIT NB. here, we create our 2-dimensional array
INDEX=. < ? $ ARRAY NB. pick an arbitrary location within our array
ARRAY=. NEW INDEX} ARRAY NB. use our new value at that location
INDEX { ARRAY NB. and return the value from that location
)

Passing two integers to task (as a list) satisfies the specifications for a two-dimensional array, but providing a longer list of integers accomplishes the same task on an array of as many dimensions as the count of integers given.

Example use (result should always be 1 which is the value of NEW):

   task 99 99
1

The type of the array is determined by the type of the values used in filling the array. E.g., alternate data types are obtained by substituting any of the following lines:

'init new' =. ' ';'x'           NB. literals
'init new' =. 1r2;2r3 NB. fractions
'init new' =. a: ; <<'Rosetta' NB. boxes

[edit] Java

import java.util.Scanner;
 
public class twoDimArray {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
 
int nbr1 = in.nextInt();
int nbr2 = in.nextInt();
 
double[][] array = new double[nbr1][nbr2];
array[0][0] = 42.0;
System.out.println("The number at place [0 0] is " + array[0][0]);
}
}

[edit] JavaScript

For the user input, requires JScript. The array processing is implementation agnostic.

var w = parseInt( get_input("Enter a width:") );
var w = parseInt( get_input("Enter a height:") );
 
// create the 2-D array
var a = new Array(h);
for (var i = 0; i < h; i++)
a[i] = new Array(w);
 
a[0][0] = 'foo';
WScript.Echo('a[0][0] = ' + a[0][0]);
 
a = null;
 
function get_input(prompt) {
output(prompt);
try {
return WScript.StdIn.readLine();
} catch(e) {
return readline();
}
}
function output(prompt) {
try {
return WScript.echo(prompt);
} catch(e) {
return print(prompt);
}
}

[edit] Liberty BASIC

Arrays can hold numbers ( eg age( 100)( or strings ( eg name$( 100)) LB arrays can only be one or two dimensioned. If an array is not DIMensioned explicitly, then the array will be limited to 11 elements, 0 to 10. Non DIMensioned double subscript arrays will be limited to 100 elements 0 to 9 by 0 to 9. The DIM statement can be followed by a list of arrays to be dimensioned, separated by commas. REDIM redimensions an already dimensioned array and clears all elements to zero (or to an empty string in the case of string arrays). This can be very useful for writing applications that have data sets of unknown size. If you dimension arrays that are extra large to make sure you can hold data, but only have a small set of data, then all the space you reserved is wasted. This hurts performance, because memory is set aside for the number of elements in the DIM statement.

 
input "Enter first array dimension "; a
input "Enter second array dimension "; b
 
dim array( a, b)
 
array( 1, 1) = 123.456
print array( 1, 1)
 
end
 


[edit]

Works with: UCB Logo
make "a2 mdarray [5 5]
mdsetitem [1 1] :a2 0  ; by default, arrays are indexed starting at 1
print mditem [1 1] :a2  ; 0

[edit] Lua

function multiply(n, a, b) if a <= b then return n, multiply(n, a + 1, b) end end
 
a, b = io.read() + 0, io.read() + 0
matrix = {multiply({multiply(1, 1, b)}, 1, a)}
matrix[a][b] = 5
print(matrix[a][b])
print(matrix[1][1])

[edit] Maple

This hardly covers the richness and complexity of arrays in Maple, but here goes:

> a := Array( 1 .. 3, 1 .. 4 ): # initialised to 0s
> a[1,1] := 1: # assign an element
> a[2,3] := 4: # assign an element
> a; # display the array
[1 0 0 0]
[ ]
[0 0 4 0]
[ ]
[0 0 0 0]
 
> a := 'a': # unassign the name
> gc(); # force a garbage collection; may or may not actually collect the array, but it will be eventually

[edit] Mathematica

 
arrayFun[m_Integer,n_Integer]:=Module[{array=ConstantArray[0,{m,n}]},
array[[1,1]]=RandomReal[];
array[[1,1]]
]


[edit] MATLAB / Octave

width = input('Array Width: ');
height = input('Array Height: ');
 
array = zeros(width,height);
 
array(1,1) = 12;
 
disp(['Array element (1,1) = ' num2str(array(1,1))]);
 
clear array; % de-allocate (remove) array from workspace
 


Sample Output:

Array Width: 18
Array Height: 12
Array element (1,1) = 12

[edit] Maxima

printf(true, "in the following terminate every number with semicolon `;'")$
n: readonly("Input x-size: ")$
m: readonly("Input y-size: ")$
a: make_array(fixnum, n, m)$
fillarray(a, makelist(i, i, 1, m*n))$
 
/* indexing starts from 0 */
print(a[0,0]);
print(a[n-1,m-1]);

[edit] MAXScript

a = getKBValue prompt:"Enter first dimension:"
b = getKBValue prompt:"Enter second dimension:"
arr1 = #()
arr2 = #()
arr2[b] = undefined
for i in 1 to a do
(
append arr1 (deepCopy arr2)
)
arr1[a][b] = 1
print arr1[a][b]

[edit] MUMPS

This example uses a two level tree to mimic an 2D array.

 
ARA2D
NEW X,Y,A,I,J
REARA
WRITE !,"Please enter two positive integers"
READ:10 !,"First: ",X
READ:10 !,"Second: ",Y
GOTO:(X\1'=X)!(X<0)!(Y\1'=Y)!(Y<0) REARA
FOR I=1:1:X FOR J=1:1:Y SET A(I,J)=I+J
WRITE !,"The corner of X and Y is ",A(X,Y)
KILL X,Y,A,I,J
QUIT
 

[edit] NetRexx

Note: No attempt is made to validate the input. Any errors will be handled as exceptions by the underlying JVM.

/* NetRexx */
options replace format comments java crossref symbols nobinary
 
say "give me the X and Y dimensions as two positive integers:"
parse ask xDim yDim
xPos = xDim % 2 -- integer divide to get close to the middle of the array
yPos = yDim % 2
 
arry = Rexx[xDim, yDim]
arry[xPos, yPos] = xDim / yDim -- make up a value...
say "arry["xPos","yPos"]:" arry[xPos, yPos]
return
 

Output:

give me the X and Y dimensions as two positive integers:
1250 1777
arry[625,888]: 0.703432752

[edit] Nimrod

import strutils, rdstdin
 
var
w = readLineFromStdin("Width: ").parseInt()
h = readLineFromStdin("Height: ").parseInt()
s = newSeq[seq[int]](h)
 
for i in 0 .. < h:
s[i].newSeq(w)

[edit] Objeck

 
use IO;
 
bundle Default {
class TwoDee {
function : Main(args : System.String[]) ~ Nil {
DoIt();
}
 
function : native : DoIt() ~ Nil {
Console->GetInstance()->Print("Enter x: ");
x := Console->GetInstance()->ReadString()->ToInt();
 
Console->GetInstance()->Print("Enter y: ");
y := Console->GetInstance()->ReadString()->ToInt();
 
if(x > 0 & y > 0) {
array : Int[,] := Int->New[x, y];
array[0, 0] := 2;
array[0, 0]->PrintLine();
};
}
}
}
 

[edit] Objective-C

Being Objective-C derivated from C, the C solution works fine in Objective-C too.

The "OpenStep" frameworks (GNUstep, Cocoa) does not provide a class for multidimensional array; of course it can be implemented in several way (also as a wrapper for the plain C way of handling arrays). Here I show a straightforward use of the NSMutableArray class.

Works with: GNUstep
Works with: Cocoa
#import <Foundation/Foundation.h>
 
int main()
{
@autoreleasepool {
int num1, num2;
scanf("%d %d", &num1, &num2);
 
NSLog(@"%d %d", num1, num2);
 
NSMutableArray *arr = [NSMutableArray arrayWithCapacity: (num1*num2)];
// initialize it with 0s
for(int i=0; i < (num1*num2); i++) [arr addObject: @0];
 
// replace 0s with something more interesting
for(int i=0; i < num1; i++) {
for(int j=0; j < num2; j++) {
arr[i*num2+j] = @(i*j);
}
}
 
// access a value: i*num2+j, where i,j are the indexes for the bidimensional array
NSLog(@"%@", arr[1*num2+3]);
}
return 0;
}

[edit] OCaml

let nbr1 = read_int ();;
let nbr2 = read_int ();;
let array = Array.make_matrix nbr1 nbr2 0.0;;
array.(0).(0) <- 3.5;;
print_float array.(0).(0); print_newline ();;

or using the module Bigarray:

let nbr1 = read_int ();;
let nbr2 = read_int ();;
let arr = Bigarray.Array2.create Bigarray.float32 Bigarray.c_layout nbr1 nbr2 ;;
arr.{0,0} <- 3.5;;
print_float arr.{0,0}; print_newline ();;

[edit] ooRexx

ooRexx arrays can be created with up to 999,999,999 dimensions...assuming you have enough memory to do so.

 
Say "enter first dimension"
pull d1
say "enter the second dimension"
pull d2
a = .array~new(d1, d2)
a[1, 1] = "Abc"
say a[1, 1]
 

[edit] Oz

Oz does not have multi-dimensional arrays. But we can create an array of arrays (similarly to most examples on this page):

declare
%% Read width and height from stdin
class TextFile from Open.file Open.text end
StdIn = {New TextFile init(name:stdin)}
Width = {String.toInt {StdIn getS($)}}
Height = {String.toInt {StdIn getS($)}}
%% create array
Arr = {Array.new 1 Width unit}
in
for X in 1..Width do
Arr.X := {Array.new 1 Height 0}
end
%% set and read element
Arr.1.1 := 42
{Show Arr.1.1}

[edit] PARI/GP

tmp(m,n)={
my(M=matrix(m,n,i,j,0));
M[1,1]=1;
M[1,1]
};

[edit] Pascal

Works with: GNU Pascal version 20060325, based on gcc-3.4.4

The following code is standard Extended Pascal (tested with gpc --extended-pascal):

program array2d(input, output);
 
type
tArray2d(dim1, dim2: integer) = array[1 .. dim1, 1 .. dim2] of real;
pArray2D = ^tArray2D;
 
var
d1, d2: integer;
data: pArray2D;
 
begin
{ read values }
readln(d1, d2);
 
{ create array }
new(data, d1, d2);
 
{ write element }
data^[1,1] := 3.5;
 
{ output element }
writeln(data^[1,1]);
 
{ get rid of array }
dispose(data);
end.

[edit] Perl

Works with: Perl version 5.x

Predefining an array (or multi-dimension array) size is unnecessary, Perl dynamically resizes the array to meet the requirements. Of course I'm assuming that the user is entering array size 0 based.

sub make_array($ $){
# get array sizes from provided params, but force numeric value
my $x = ($_[0] =~ /^\d+$/) ? shift : 0;
my $y = ($_[0] =~ /^\d+$/) ? shift : 0;
 
# define array, then add multi-dimensional elements
my @array;
$array[0][0] = 'X '; # first by first element
$array[5][7] = 'X ' if (5 <= $y and 7 <= $x); # sixth by eighth element, if the max size is big enough
$array[12][15] = 'X ' if (12 <= $y and 15 <= $x); # thirteenth by sixteenth element, if the max size is big enough
 
# loop through the elements expected to exist base on input, and display the elements contents in a grid
foreach my $dy (0 .. $y){
foreach my $dx (0 .. $x){
(defined $array[$dy][$dx]) ? (print $array[$dy][$dx]) : (print '. ');
}
print "\n";
}
}

The above is a bit verbose, here is a simpler implementation:

sub array {
my ($x, $y) = @_;
map {[ (0) x $x ]} 1 .. $y
}
 
my @square = array 3, 3;
 
# everything above this line is mostly redundant in perl,
# since perl would have created the array automatically when used.
# however, the above function initializes the array elements to 0,
# while perl would have used undef
#
# $cube[3][4][5] = 60 # this is valid even if @cube was previously undefined
 
$square[1][1] = 1;
print "@$_\n" for @square;
> 0 0 0
> 0 1 0
> 0 0 0

[edit] Perl 6

my ($major,$minor) = prompt("Dimensions? ").comb(/\d+/);
my @array := [ for ^$major { [ for ^$minor {'@'} ] } ];
@array[ pick 1, ^$major ][ pick 1, ^$minor ] = ' ';
.say for @array;

Line 1: The input parse doesn't care how you separate the dimensions as long as there are two distinct numbers.

Line 2: Any bracketing construct in Perl 6 may contain a statement. Also, any loop returns a list of each of its iteration's results. Together these make it trivial to write most kinds of list comprehensions. In this case all the loop iterations return the identical initial value for that array element. The ^$major construct is short for 0..^$major, that is, all the integers up to (but not including) $major.

Line 3: Again we use the "upto" operator, but this time just pick one of the numbers for each dimension.

Line 4: Print each line of the array. When each subarray is converted to a string, it automatically gets a space between elements. Any method call without an object defaults to the current topic, so .say really means $_.say. There is no need in Perl 6 to remember which functions default to $_.

Typical run:

$ ./two-dee
Dimensions? 5x35
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @
@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @

[edit] PicoLisp

(de 2dimTest (DX DY)
(let A (make (do DX (link (need DY))))
(set (nth A 3 3) 999) # Set A[3][3] to 999
(mapc println A) # Print all
(get A 3 3) ) ) # Return A[3][3]
 
(2dimTest 5 5)

Output:

(NIL NIL NIL NIL NIL)
(NIL NIL NIL NIL NIL)
(NIL NIL 999 NIL NIL)
(NIL NIL NIL NIL NIL)
(NIL NIL NIL NIL NIL)
-> 999

[edit] PL/I

 
/* First way using a controlled variable: */
 
declare A(*,*) float controlled;
get list (m, n);
allocate A(m,n);
get list (A);
put skip list (A);
 
/* The array remains allocated until the program terminates, */
/* or until explicitly destroyed using a FREE statement. */
 
free A;
 
 6.00000E+0000           5.00000E+0000           4.00000E+0000           3.00000E+0000           2.00000E+0000          
1.00000E+0000
 
 
/* Second way using a BEGIN block: */
 
get list (m, n);
begin;
declare A(m, n) float;
get list (A);
put skip list (A);
end;
 
/* The array is automatically destroyed when the block terminates. */
 
 1.00000E+0000           2.00000E+0000           3.00000E+0000           4.00000E+0000           5.00000E+0000          
6.00000E+0000 7.00000E+0000 8.00000E+0000 9.00000E+0000 1.00000E+0001
1.10000E+0001 1.20000E+0002
 
 
/* Third way using a PROCEDURE block: */
 
get list (m, n);
call S (m, n);
S: procedure (m, n);
declare A(m, n) float;
get list (A);
put skip list (A);
end S;
 
/* The array is automatically destroyed when the procedure terminates. */
 
 
1.00000E+0000 2.00000E+0000 3.00000E+0000 4.00000E+0000 5.00000E+0000
6.00000E+0000 7.00000E+0000 8.00000E+0000 9.00000E+0000 1.00000E+0001
1.10000E+0001 1.20000E+0001 1.30000E+0001 1.40000E+0001 1.50000E+0001
1.60000E+0001 1.70000E+0001 1.80000E+0001 1.90000E+0001 2.00000E+0001
 

[edit] Pop11

vars itemrep;
incharitem(charin) -> itemrep;
;;; Read sizes
vars n1 = itemrep(), n2= itemrep();
;;; Create 0 based array
vars ar = newarray([0 ^(n1 - 1) 0 ^(n2 - 1)], 0);
;;; Set element value
15 -> ar(0, 0);
;;; Print element value
ar(0,0) =>
;;; Make sure array is unreferenced
0 -> ar;

Pop11 is garbage collected so there is no need to destroy array. However, the array is live as long as variable ar references it. The last assignment makes sure that we loose all our references to the array turning it into garbage.

Pop11 arrays may have arbitrary lower bounds, since we are given only size we create 0 based array.

[edit] PureBasic

If OpenConsole()
Define x, y
 
Print("Input X-Size: ")
x = Val(Input())
 
Print("Input Y-Size: ")
y = Val(Input())
 
Dim a(x,y) ; Should really check if x & y are larger then 1, but that would be less fun....
 
a(1,1)=Random(1000)
PrintN("a(1,1)= " + Str(a(1,1)) )
 
PrintN("Press ENTER to exit"):Input()
End ; Close down and let PureBasic delete the Console and all variables.
EndIf

[edit] Python

Works with: Python version 2.5
width = int(raw_input("Width of myarray: "))
height = int(raw_input("Height of Array: "))
myarray = [[0] * width for i in xrange(height)]
myarray[0][0] = 3.5
print myarray[0][0]

Note: Some people may instinctively try to write myarray as [[0] * width] * height, but the * operator creates n references to [[0] * width]

You can also use a two element tuple to index a dictionary like so:

myarray = {(w,h): 0 for w in range(width) for h in range(height)}
# or, in pre 2.7 versions of Python: myarray = dict(((w,h), 0) for w in range(width) for h in range(height))
myarray[(0,0)] = 3.5
print myarray[(0,0)]

[edit] R

Translation of: C
input <- readline("Enter two integers.  Space delimited, please:  ")
dims <- as.numeric(strsplit(input, " ")[[1]])
arr <- array(dim=dims)
ii <- ceiling(dims[1]/2)
jj <- ceiling(dims[2]/2)
arr[ii, jj] <- sum(dims)
cat("array[", ii, ",", jj, "] is ", arr[ii, jj], "\n", sep="")

[edit] Racket

Using a vector of vectors to represent arrays:

 
#lang racket
 
(printf "Enter XY dimensions: ")
(define xy (cons (read) (read)))
(define array (for/vector ([x (car xy)]) (for/vector ([y (cdr xy)]) 0)))
 
(printf "Enter a number for the top-left: ")
(vector-set! (vector-ref array 0) 0 (read))
(printf "Enter a number for the bottom-right: ")
(vector-set! (vector-ref array (sub1 (car xy))) (sub1 (cdr xy)) (read))
 
array
 

Output:

Enter XY dimensions: 3 3
Enter a number for the top-left: 1
Enter a number for the bottom-right: 9
'#(#(1 0 0) #(0 0 0) #(0 0 9))

[edit] REXX

/*REXX program to  allocate/populate/display  a two-dimensional array.  */
call bloat
/*no more array named A. at this point.*/
exit /*stick a fork in it, we're all done. */
/*─────────────────────────BLOAT subroutine─────────────────────────────*/
bloat: procedure; say
say 'Enter two positive integers (a 2-dimensional array will be created).'
pull n m . /*there is no way to pre-allocate an array,*/
/*REXX will allocate each element when it's*/
/*assigned. */
 
a.='~' /*default value for all elements so far. */
/*this ensures every element has a value. */
do j =1 for n
do k=1 for m
if random()//7==0 then a.j.k=j'_'k /*populate every 7th random*/
end /*k*/
end /*j*/
 
do r=1 for n /*display array to the console (row,col). */
_=
do c=1 for m
_=_ right(a.r.c,4) /*display one row at a time, align the vals*/
end /*kk*/
say _
end /*jj*/
/*when the RETURN is executed (from a */
/*PROCEDURE in this case), the array A. is*/
/*"de-allocated", that is, it's no longer */
/*defined, and the memory that the array */
/*has is now free for other REXX variables.*/
 
/*If the BLOAT subroutine didn't have */
/*a "PROCEDURE" on that statement, the */
/*array "a." would be left intact. */
 
/*The same effect is performed by a DROP. */
drop a. /*because of the PROCEDURE statement, */
return /* the DROP statement is superfluous. */

output when the following input is entered after the prompt message: 30 15

    ~  1_2    ~    ~    ~    ~    ~  1_8  1_9 1_10 1_11    ~    ~    ~    ~
  2_1  2_2    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~ 2_13    ~    ~
    ~    ~  3_3  3_4    ~    ~    ~    ~    ~ 3_10    ~    ~    ~    ~    ~
    ~    ~    ~    ~    ~    ~  4_7    ~    ~    ~ 4_11    ~    ~    ~    ~
    ~    ~    ~    ~  5_5    ~    ~    ~    ~    ~    ~    ~    ~    ~ 5_15
    ~    ~  6_3    ~    ~    ~  6_7    ~    ~ 6_10    ~    ~    ~    ~    ~
  7_1    ~    ~  7_4    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~
    ~  8_2    ~    ~    ~    ~  8_7    ~    ~    ~    ~    ~    ~    ~    ~
    ~  9_2    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~ 9_15
    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~
 11_1    ~    ~    ~ 11_5    ~    ~ 11_8 11_9    ~    ~    ~    ~    ~    ~
    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~
    ~ 13_2    ~ 13_4    ~    ~    ~    ~    ~    ~    ~    ~ 3_13 3_14    ~
    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~ 4_11    ~    ~    ~    ~
    ~ 15_2    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~
    ~ 16_2    ~ 16_4    ~    ~    ~    ~    ~    ~ 6_11    ~    ~    ~    ~
 17_1    ~ 17_3    ~    ~ 17_6    ~    ~    ~ 7_10    ~    ~    ~    ~ 7_15
    ~    ~    ~    ~ 18_5    ~    ~    ~    ~ 8_10    ~    ~    ~ 8_14    ~
    ~ 19_2    ~    ~    ~    ~    ~    ~    ~    ~ 9_11    ~    ~    ~    ~
    ~    ~    ~    ~    ~    ~ 20_7    ~    ~    ~    ~    ~    ~    ~    ~
    ~    ~    ~    ~ 21_5    ~    ~    ~    ~ 1_10    ~    ~    ~    ~ 1_15
    ~ 22_2    ~    ~    ~    ~    ~    ~ 22_9    ~ 2_11 2_12    ~    ~    ~
    ~    ~    ~    ~ 23_5    ~    ~    ~    ~    ~ 3_11 3_12    ~ 3_14    ~
    ~    ~    ~    ~    ~ 24_6    ~ 24_8 24_9    ~    ~ 4_12    ~    ~    ~
 25_1    ~    ~    ~    ~ 25_6 25_7    ~    ~ 5_10    ~    ~    ~    ~    ~
    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~    ~
    ~    ~    ~    ~    ~    ~ 27_7    ~ 27_9    ~    ~    ~ 7_13    ~    ~
    ~    ~    ~    ~    ~    ~    ~    ~    ~ 8_10    ~    ~    ~    ~    ~
    ~ 29_2    ~    ~ 29_5    ~    ~    ~    ~ 9_10    ~    ~    ~    ~    ~
    ~ 30_2 30_3    ~ 30_5    ~    ~ 30_8 30_9    ~    ~    ~ 0_13    ~    ~

[edit] Ruby

puts 'Enter width and height: '
w=gets.to_i
arr = Array.new(gets.to_i){Array.new(w)}
arr[1][3] = 5
p arr[1][3]

[edit] Run BASIC

print "Enter array 1 greater than 0"; : input a1
print "Enter array 2 greater than 0"; : input a2
 
dim chrArray$(max(a1,1),max(a2,1))
dim numArray(max(a1,1),max(a2,1))
 
chrArray$(1,1) = "Hello"
numArray(1,1) = 987.2
print chrArray$(1,1);" ";numArray(1,1)

[edit] Scala

object Array2D{
def main(args: Array[String]): Unit = {
val x = Console.readInt
val y = Console.readInt
 
val a=Array.fill(x, y)(0)
a(0)(0)=42
println("The number at (0, 0) is "+a(0)(0))
}
}

[edit] Seed7

$ include "seed7_05.s7i";
 
const proc: main is func
local
var integer: numRows is 0;
var integer: numCols is 0;
var array array integer: anArray is 0 times 0 times 0;
begin
write("Give me the numer of rows: ");
readln(numRows);
write("Give me the numer of columns: ");
readln(numCols);
anArray := numRows times numCols times 0;
anArray[1][1] := 3;
writeln("The number at place [1, 1] is " <& anArray[1][1]);
end func;

Output:

Give me the numer of rows: 5
Give me the numer of columns: 7
The number at place [1, 1] is 3

[edit] Smalltalk

Works with: Pharo
 
m := (FillInTheBlankMorph request: 'Number of rows?') asNumber.
n := (FillInTheBlankMorph request: 'Number of columns?') asNumber.
aMatrix := Matrix rows: m columns: n.
aMatrix
at: (aMatrix rowCount // 2)
at: (aMatrix columnCount // 2)
put: 3.4.
e := aMatrix
at: (aMatrix rowCount // 2)
at: (aMatrix columnCount // 2).
Transcript show: 'Entry is', e printString.
 
Works with: GNU Smalltalk

Smalltalk has no problems in creating objects at runtime. I haven't found a class for multidimensional array in the standard library, so let us suppose to have a class named MultidimensionalArray.

|num1 num2 arr|
num1 := stdin nextLine asInteger.
num2 := stdin nextLine asInteger.
 
arr := MultidimensionalArray new: { num1. num2 }.
 
1 to: num1 do: [ :i |
1 to: num2 do: [ :j |
arr at: { i. j } put: (i*j)
]
].
 
1 to: num1 do: [ :i |
1 to: num2 do: [ :j |
(arr at: {i. j}) displayNl
]
].

A possible implementation for a BidimensionalArray class is the following (changing Multi into Bi and using this class, the previous code runs fine):

Object subclass: BidimensionalArray [
|biArr|
<comment: 'bidim array'>
].
BidimensionalArray class extend [
new: biDim [ |r|
r := super new.
r init: biDim.
^ r
]
].
BidimensionalArray extend [
init: biDim [
biArr := Array new: (biDim at: 1).
1 to: (biDim at: 1) do: [ :i |
biArr at: i put: (Array new: (biDim at: 2))
].
^ self
]
at: biDim [
^ (biArr at: (biDim at: 1)) at: (biDim at: 2)
]
at: biDim put: val [
^ (biArr at: (biDim at: 1)) at: (biDim at: 2) put: val
]
].

Instead of implementing such a class (or the MultidimensionalArray one), we can use a LookupTable class, using Array objects as keys (each element of the array will be an index for a specific dimension of the "array"). The final effect is the same as using an array (almost in the AWK sense) and the approach has some advantages.

|num1 num2 pseudoArr|
num1 := stdin nextLine asInteger.
num2 := stdin nextLine asInteger.
 
"we can 'suggest' an initial value for the number
of ''slot'' the table can hold; anyway, if we use
more than these, the table automatically grows"

pseudoArr := LookupTable new: (num1 * num2).
 
1 to: num1 do: [ :i |
1 to: num2 do: [ :j |
pseudoArr at: {i. j} put: (i * j).
]
].
 
1 to: num1 do: [ :i |
1 to: num2 do: [ :j |
(pseudoArr at: {i. j}) displayNl.
]
].

[edit] SNOBOL4

Works with: Macro Spitbol
Works with: Snobol4+
Works with: CSnobol

Note: trim(input) is needed for Snobol4+.

*       # Get user X,Y dimensions
output = 'Enter X,Y:'; xy = trim(input)
xy break(',') . x ',' rem . y
 
* # Define and create array, 1-based
arr = array(x ',' y) ;* Or arr = array(xy)
 
* # Display array prototype
output = 'Prototype: ' prototype(arr)
 
* # Assign elements, angle or square brackets
* # Same array can hold ints, strings, etc.
arr<x,y> = 99; arr[1,1] = 'dog'
 
* # Display elements
output = 'arr[' xy '] = ' arr[x,y]
output = 'arr[1,1] = ' arr[1,1]
 
* # Release array for garbage collection
arr =
end

Output:

Enter X,Y:
5,5
Prototype: 5,5
arr[5,5] = 99
arr[1,1] = dog

[edit] Standard ML

val nbr1 = valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn);
val nbr2 = valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn);
val array = Array2.array (nbr1, nbr2, 0.0);
Array2.update (array, 0, 0, 3.5);
print (Real.toString (Array2.sub (array, 0, 0)) ^ "\n");

[edit] Tcl

Works with: Tcl version 8.5
package require Tcl 8.5
 
puts "enter X dimension:"
set dim2 [gets stdin]
puts "enter Y dimension:"
set dim1 [gets stdin]
# Make the "array"; we'll keep it in row-major form
set l [lrepeat $dim1 [lrepeat $dim2 {}]]
# Select a point at around the middle of the "array"
set y [expr {$dim1>>1}]
set x [expr {$dim2>>1}]
# Set the value at that point
lset l $y $x aValue
# Read the value at that point
puts [lindex $l $y $x]
# Delete the "array"
unset l

[edit] Toka

Toka has no direct support for 2D arrays, but they can be created and operated on in a manner similar to normal arrays using the following functions.

[ ( x y -- address )
cells malloc >r
dup cells >r
[ r> r> r> 2dup >r >r swap malloc swap i swap array.put >r ] iterate
r> r> nip
] is 2D-array
 
[ ( a b address -- value )
array.get array.get
] is 2D-get-element
 
[ ( value a b address -- )
array.get array.put
] is 2D-put-element

And a short test:

5 5 2D-array >r             #! Create an array and save the pointer to it
10 2 3 r@ 2D-put-element #! Set element 2,3 to 10
2 3 r@ 2D-get-element #! Get the element at 2,3
r> drop #! Discard the pointer to the array

[edit] Vim Script

" Create a two-dimensional array with r rows and c columns.
" The optional third argument specifies the initial value

" (default is 0).

function MakeArray(r, c, ...)
if a:0
let init = a:1
else
let init = 0
endif
 
let temp = []
for c in range(a:c)
call add(temp, init)
endfor
 
let array = []
for r in range(a:r)
call add(array, temp[:])
endfor
return array
endfunction
 
let rows = input("Enter number of rows: ")
let cols = input("Enter number of columns: ")
echo "\n"
let array = MakeArray(rows, cols)
let array[rows - 1][cols - 1] = rows * cols
echo array[rows - 1][cols - 1]
unlet array

[edit] XPL0

inc     c:\cxpl\codes;  \(command words can be abbreviated to first 3 letters)
def IntSize=4; \number of bytes in an integer (2 or 4 depending on version)
int X, Y, A, I;
[X:= IntIn(0); Y:= IntIn(0); \get 2 dimensions from user
A:= Reserve(X*IntSize);
for I:= 0 to X-1 do A(I):= Reserve(Y*IntSize);
A(X/2, Y/2):= X+Y;
IntOut(0, A(X/2, Y/2)); CrLf(0);
]

Space allocated by the Reserve intrinsic is automatically released when the procedure that calls Release returns.

Example of a 12000x100 integer array for a total of 1.2 million integers:

12000 100
12100
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