Question

void f(int **m, int w, int h )  
{       
int i,j;

    for(i=0;i < w ; i++)  
    {    
      for(j=0;j<h;j++)
      {
         printf("%5d", m[i][j]); //  *( *(m + i) + j ) ??
      }

    printf("\n");
    }
    return;
}


int main()
{

int a[3][3]={{1,2,3},{4,5, 6},{7,8,9}};


f(a,3,3);

}

this code is trying to print a 2d matrix
but i get a segmentation fault.

Answer 1

Your matrix is not of type int **, its type is int[3][].

int ** means a pointer to an array of pointers. You don’t have an array of pointers, you have an array of 3-integer-arrays. It’s not the same thing.

If you want you can change your code to take that into account.

int *addr = (int *)m;  // This is the address of m[0][0]

To access m[i][j] use:

int elem = addr[i*h+j];