题解 | #字符个数统计#

#include <stdio.h>

int main() {
    int ret[128] = {0};
    char arr[510];
    gets(arr);
    int i = 0;
    while(arr[i] != '\0')
    {
        if (arr[i] == '\n'){
            break;
        }
        int tmp = arr[i];
        ret[tmp] = 1;
        i++;
    }
    for (i = 1; i < 128; i++)
    {
        ret[0] += ret[i];
    }
    printf("%d", ret[0]);
    return 0;
}