题解 | #统计字符#

#include <bits/stdc++.h>
#include <iostream>
using namespace std;

int main() {
    string text;
    while (getline(cin, text)) { // 注意 while 处理多个 case
        int a = 0, b = 0, c = 0, d = 0;
        for (const char ch : text) {
            if (isalpha(ch)) {
                a++;
            } else if (1 == isblank(ch)) {
                b++;
            } else if (1 == isdigit(ch)) {
                c++;
            } else {
                d++;
            }
        }
        cout << a << endl << b << endl << c << endl << d << endl;
    }
}