题解 | 统计字符

#include <iostream>
using namespace std;

int main() {
    string s;
    int cnt_letter = 0, cnt_blank = 0, cnt_num = 0, cnt_other = 0;
    while (getline(cin, s)) {
        for (char i : s) {
            if ((i >= 'A' && i <= 'Z') || (i >= 'a' && i <= 'z') )
                ++cnt_letter;
            else if ( i == ' ')
                ++cnt_blank;
            else if ( i >= '0' && i <= '9')
                ++cnt_num;
            else ++cnt_other;
        }
        cout << cnt_letter << endl << cnt_blank << endl << cnt_num << endl << cnt_other
             << endl;
    }
    return 0;
}