int *build_array(char **strs, int size) {
  int *int_array = malloc(sizeof(int) * size);
  for(int i = 0; i < size; i++){
    int_array[i] = strtol(strs[i], NULL, 10);
  }
  return int_array;
}

return a pointer to an array of ints, which is strs all converted to ints