题解 | 字符个数统计

#include <iostream>
using namespace std;
#define I int
#define LL long long

void countn() ;

int main() {
	countn();

	return 0;
}

void countn() { //字符个数统计
	I num[100] = {0}, t = 0;
	char a;
	while (cin >> a)
		num[a - '!']++;
	for (I i = 0; i < 100; i++)
		if (num[i])
			t++;
	cout << t;
}