题解 | #图片整理#

#include<stdio.h>
int main()
{
    char arr[501] = {'\0'};//存放字符串
    int count[128] = {0};//把字符串对应的ascii码作为下标
    int sum = 0;//计算不同字符个数
    scanf("%s",arr);
    for (int i = 0; i < strlen(arr); ++i)
    {
        count[arr[i]]++;
    }
    //只要不为0 sum就加
    for(int i = 0; i < 128; ++i)
    {
        if(count[i])
            sum++;
    }
    printf("%d",sum);
}