找第一个只出现一次的字符

#include<stdio.h>
#include<string.h>
char a[100005];

int main(){
    int f = 0;
    scanf("%s" , a);
    int ll = strlen(a);
    for(int i = 0;i < ll;i++){
        int x = 0;
        if(a[i] == ‘*‘)
            continue;
        for(int j = i+1;j < ll;j++){
            if(a[j] == ‘*‘)
                continue;
            if(a[i] == a[j])
                {
                    x= 1;
                    a[j] = ‘*‘;
                    continue;
                }
        }
        if(x == 0){
            printf("%c",a[i]);
            f = 1;
            break;
        }

    }
    if(f == 0)
        printf("no");
    return 0;
}

#include<stdio.h>
#include<string.h>
int a[26];
char b[100005];
int main(){
    memset(a,0,sizeof(a));
    char c;
    int i = 0;
    int f =0;
    scanf("%s",b);
    int bl = strlen(b);
    for(int i =0;i < bl;i++){
        int x = b[i] - 97;
        a[x] = a[x] + 1;
    }

    for(int i =0; i < bl;i++){
        int x = b[i] - 97;
        if(a[x] == 1){
            printf("%c",b[i]);
            f = 1;
            break;
        }
    }
    if(f == 0)
        printf("no");
    return 0;
}