Create a two-dimensional array at runtime

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.

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 oputput that element. Finally destroy the array if not done by the language itself.

Ada

with Ada.Text_Io; use Ada.Text_Io;
with Ada.Float_Text_Io; use Ada.Float_Text_Io;
with Ada.Integer_Text_Io; use 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
   Get(Item => Dim_1);
   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;
      Put(Item => Matrix(1, Dim_2), Fore => 1, Aft => 5, Exp => 0);
      New_Line;
   end;
   -- The variable Matrix is popped off the stack automatically
end Two_Dimensional_Arrays;

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()
}

Python

Interpreter: Python 2.5

 width = int(raw_input("Width of array: "))
 height = int(raw_input("Height of Array: "))
 array = [[0] * width for i in range(height)]
 array[0][0] = 3.5

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

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