#include <iostream>
#include <vector>
#include <string>

using namespace std;

struct Student {
	string name;
	int id;
	float score;
};

vector<Student> students;

void inputData() {
	Student student;
	cout << "请输入学生姓名：";
	cin >> student.name;
	cout << "请输入学生学号：";
	cin >> student.id;
	cout << "请输入学生成绩：";
	cin >> student.score;
	students.push_back(student);
	cout << "录入成功！" << endl;
}

void modifyOrDeleteData() {
	int id;
	cout << "请输入要修改/删除的学生学号：";
	cin >> id;
	for (auto it = students.begin(); it != students.end(); ++it) {
		if (it->id == id) {
			cout << "学生姓名：" << it->name << "，学号：" << it->id << "，成绩：" << it->score << endl;
			cout << "请输入新的成绩（输入-1表示删除该学生信息）：";
			float newScore;
			cin >> newScore;
			if (newScore == -1) {
				students.erase(it);
				cout << "删除成功！" << endl;
			} else {
				it->score = newScore;
				cout << "修改成功！" << endl;
			}
			return;
		}
	}
	cout << "未找到该学生信息！" << endl;
}

void viewStatistics() {
	float totalScore = 0;
	for (const auto& student : students) {
		totalScore += student.score;
	}
	float averageScore = students.empty() ? 0 : totalScore / students.size();
	cout << "学生人数：" << students.size() << "，总成绩：" << totalScore << "，平均成绩：" << averageScore << endl;
}

int main() {
	while (true) {
		cout << "学生成绩信息管理系统菜单：" << endl;
		cout << "1. 数据录入" << endl;
		cout << "2. 数据修改/删除" << endl;
		cout << "3. 统计查看" << endl;
		cout << "4. 退出系统" << endl;
		cout << "请选择功能编号：";
		
		int choice;
		cin >> choice;
		
		switch (choice) {
		case 1:
			inputData();
			break;
		case 2:
			modifyOrDeleteData();
			break;
		case 3:
			viewStatistics();
			break;
		case 4:
			cout << "感谢使用！" << endl;
			return 0;
		default:
			cout << "无效的功能编号！" << endl;
		}
	}
	
	return 0;
}