大佬，我编译错误，自己没有找到错误（求）

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

struct sdt {
	string num;
	double grade;
} stu1[50] = {};
sdt stu2[50] = {};
bool cmp_score(sdt x, sdt y) {
	return x.grade > y.grade;
}

int n;
int main() {
	cin >> n;
	string u;
	int k1 = 0, k2 = 0;
	for (int i = 0; i < n; i++) {
		cin >> u;
		if (u[0] == 'm') {
			stu1[k1 ++].num = u;
			cin >> stu1[k1 ++].grade;
		} else {
			stu2[k2 ++].num = u;
			cin >> stu2[k2 ++].grade;
		}
	}
	sort(stu1, stu1 + k1);
	sort(stu2, stu2 + k2, cmp_score);
	for (int i = 0; i < k1 - 1; i++) {
		cout << stu1[i].num << ' ' << stu1[i].grade << endl;
	}
	for (int i = 0; i < k2 - 1; i++) {
		cout << stu2[i].num << ' ' << stu2[i].grade << endl;
	}

	return 0;
}