Question

I can’t seem to figure out what I’m doing wrong.

int main(int argc, char **argv) {
  int height = 4, width = 6;
  int **map;
  map = (int **)(malloc(height * sizeof(int*)));
  for(i = 0; i < height; i++) {
    map[i] = (int *)(malloc(width * sizeof(int)));
  }
  fill_map(&map, height, width);
}

void fill_map(int ***map, int height, int width) {
  int i, k, character;
  for(i = 0; i < height; i++) {
    k = 0;
    while((character = getchar()) != '\n') {
        *map[i][k] = character;
        k++;
    }
  }
}

I get a segfault in fill_map, in the inner while loop, why?

Answer 1

Don’t send &map to the function, change the prototype to receive (int **map) or, use (*map)[i][k]. This is because indirection operator * has lower precedence than [] operator.