How to dynamic allocate a two dimensional array

Question

I would like to make a two dimensional array in C.

For example, I make an int type variable named place like this:

int *place;

I ha

Answer 1

Let place be a pointer to arrays,

int (*place)[columns] = malloc(rows * sizeof *place);

That gives you a contiguous block of memory (good for locality) that you can simply access with

place[i][j] = whatever;

Answer 2

You need to do the following to allocate arr[x][y] of type int dynamically:

 int i = 0;
 int **arr = (int**)calloc(x, sizeof(int*));
 for(i = 0; i < x; i++)
      arr[i] = (int *) calloc(y, sizeof(int));

The idea is to first create a one dimensional array of pointers, and then, for each array entry, create another one dimensional array.

Answer 3

You could use a single 1d array as a 2d array by some smart indexing :

Allocate memory :

place = (int*) malloc(rows * columns * sizeof(int));

To access place[i][j], use i and j as :

place[ i*columns + j] = value ;