hash function 字符串哈希函数

#include <stdio.h>

int hash(const char *str) {
  int sum = ;
  for (int i=;;i++) {
    if (str[i] == '\0') break;
    sum += ((int)str[i] *  + i);
  }

  return sum%;
}

int  main(int argc, char **argv) {
  if (argc < ) {
    printf("usage: a.out string\n");
  } else {
    printf("%d\n", hash(argv[]));
  }

  return ;
}