Question

I cannot create a 2D array from 2 variables (eg int arr[i][j] not allowed) so how would I create a dynamically sized 2D array?

The dimensions of the array are only known at runtime in my program. The array is to represent a grid. How would I code this in C?

Answer 1

You have to allocate a 1-dimensional array:

int* array = calloc(m*n, sizof(int));

And access it like this:

array[i*n + j]

The compiler does exactly this when accessing two-dimensional arrays, and will probably output the same code when n can be guessed at compile time.