题解 | 字符个数统计

#include <iostream>
using namespace std;

int main() {
    string s;
    int cnt = 0;
    while (getline(cin, s)) {
        int arr[128] = {0};
        for (int i = 0; i < s.size(); ++i) {
            arr[s[i]] = 1; //用数组存储该ascii码是否存在于字符串中
        }
        for (int j = 0; j < 128; ++j) {
            if (arr[j] == 1)
                ++cnt;
        }
        cout << cnt;
    }
    return 0;
}