组合类相关题目

定义一个组合类课程类Lesson，其数据成员有：课号id，课程名name，任课老师teacher，选课学生s，其中学生信息定义成学生类的数组。成员函数有：AddStudent增加选课学生信息，GetPassRate计算课程的及格率，ShowInfo显示课程信息。学生类包括学号、姓名及该门课的成绩。用上述类的组合实现课程的管理。

#include <iostream>
#include <string.h>
using namespace std;
class Student{
	public:
		Student(){}
		Student(string a,string b,float c):num(a),name(b),score(c){}
		void display();	//显示学生信息函数
	private:
		string num;	//学生学号
		string name;
		float score;
};
class Lesson{
	public:
		Lesson(string x,string y,string z):id(x),name(y),teacher(z){}
		void AddStudent();
		void GetPassRate();
		void ShowInfo();
		static int count;	//使用静态变量更好
		static int total;
		static float rate;
	private:
		string id;
		string name;
		string teacher;
		Student s[70];	//使用数组，能够灵活录入多个学生信息
};
int Lesson::count=0;	//类外初始化变量
int Lesson::total=0;
float Lesson::rate=-1;
void Student::display()
{
	cout<<"id:"<<num<<endl<<"name:"<<name<<endl<<"score:"<<score<<endl;
}
void Lesson::AddStudent()
{
	int x;
	string num;
	string name;
	float score;
	for(int i=0;i<70;i++)
	{
		cout<<"Please input student"<<i+1<<"'s id,name and score:"<<endl;
		cin>>num>>name>>score;
		s[i]=Student(num,name,score);
		if(score>=60)
		count++;
		total++;
		cout<<"input 0 to exit,or any other number to continue:";//退出录入功能
		cin>>x;
		if(x==0)
		break; 
	}
}
void Lesson::GetPassRate()
{
	rate=(float)count/total;
}
void Lesson::ShowInfo()
{
	int k=0;
	cout<<"Lesson's id:"<<id<<endl<<"Name:"<<name<<endl<<"Teacher:"<<teacher<<endl;
	cout<<"The pass rate is "<<rate<<endl;
	for(;k<total;k++)
	s[k].display();
}
int main()
{
	Lesson L1("01","Math","Li");
	L1.AddStudent();
	L1.GetPassRate();
	L1.ShowInfo();
	return 0;
}