来自刘华强的答案

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

int main() {

string a;
getline(cin, a);
int b = a.size();
int d = 0, x = 0, s = 0, k = 0, t = 0;
for (int i = 0; i < b; i++) {
	if (a[i] <= 'Z' && a[i] >= 'A') {
		d++;
	} else if (a[i] <= 'z' && a[i] >= 'a') {
		x++;
	} else if (a[i] == '0' || a[i] == '1' || a[i] == '2' || a[i] == '3' || a[i] == '4' || a[i] == '5' || a[i] == '6'
	           || a[i] == '7' || a[i] == '8' || a[i] == '9') {
		s++;
	} else if (a[i] == ' ') {
		k++;
	} else {
		t++;
	}
}
cout << d << "\n" << x << "\n" << s << "\n" << k << "\n" << t;
return 0;
}