How do I work with dynamic multi-dimensional arrays in C?

Question

Does someone know how I can use dynamically allocated multi-dimensional arrays using C? Is that possible?

Answer 1

Here is working code that defines a subroutine make_3d_array to allocate a multidimensional 3D array with N1, N2 and N3 elements in each dimension, and then populates it with random numbers. You can use the notation A[i][j][k] to access its elements.

#include 
#include 
#include 


// Method to allocate a 2D array of floats
float*** make_3d_array(int nx, int ny, int nz) {
    float*** arr;
    int i,j;

    arr = (float ***) malloc(nx*sizeof(float**));

    for (i = 0; i < nx; i++) {
        arr[i] = (float **) malloc(ny*sizeof(float*));

        for(j = 0; j < ny; j++) {
            arr[i][j] = (float *) malloc(nz * sizeof(float));
        }
    }

    return arr;
} 



int main(int argc, char *argv[])
{
    int i, j, k;
    size_t N1=10,N2=20,N3=5;

    // allocates 3D array
    float ***ran = make_3d_array(N1, N2, N3);

    // initialize pseudo-random number generator
    srand(time(NULL)); 

    // populates the array with random numbers
    for (i = 0; i < N1; i++){
        for (j=0; j