3D matrix in C with memory allocation

3d_matrix.c

int main() {
  grid = (int***)malloc(num_players * sizeof(int**));
  for (int i = 0; i < num_players; i++) {
  	grid[i] = (int**)calloc(num_lines, sizeof(int*));
    for (int j = 0; j < num_lines; j++) {
	    grid[i][j] = (int*)calloc(num_cols, sizeof(int));
    }
  }
}