字母求和c++三级

代码

#include <iostream>
#include <assert.h>
#include <cstdlib>
#include <cstdio>
#include <cstring>
using namespace std;
const int N = 100005;
char str[N];
int main() {
	int n;
	cin >> n;
	cin >> str;
	assert(n == strlen(str));
	int ans = 0;
	for (int i = 0; i < n; i ++) {
		if (str[i] >= 'a' && str[i] <= 'z')
			ans += str[i] - 'a' + 1;
		else if (str[i] >= 'A' && str[i] <= 'Z')
			ans -= str[i];
		else
			assert(false);
	}
	cout << ans << endl;
	return 0;
}