题目：在字符串中找出第一个只出现一次的字符。如输入"abaccdeff"，这输出'b'

// 第一个只出现一次的字符#include 
     
      char first_not_repeat_char(char *s){    int count[256]={
   0};    char *pkey;    if( s==NULL )    {        printf("The string should not be NULL\n");        return '\0';    }    for(pkey=s; *pkey != '\0'; pkey++)        count[*pkey]++;    for(pkey=s; *pkey != '\0'; pkey++)        if( count[*pkey] == 1 )            return *pkey;    return '\0';}int main(void){    char s[1001];    printf("Please input a string: ");    scanf("%s",s);    char first = first_not_repeat_char(s);    if(first != '\0')        printf("First not repeat char is: %c\n",first);    else        printf("Not found\n");    char *p=0;    return 0;}