应用举例

例 1：建立一个简单的大学管理系统，其中有学生类、职工类、教师类和在职大学生类，类的继承关系如下图：

其中，Data_rec 是虚基类，它包含了所有派生类共有的数据成员，职工类 Employee 和学生类 Student 为虚基类 Data_rec 的派生类，教师类 Teacher 为职工类 Employee 的派生类，在职大学生类 E_Student 是职工类 Employee 和学生类 Student 的共同派生类。每个类定义了一个相对于特定类的不同的 print 函数，输出各类的数据成员。

#include
#include
using namespace std;
class Data_rec{		//声明基类 Data_rec 
	protected:
		string name;	//姓名
		char sex;	    //性别
		int age;	    //年龄 
	public:
		Data_rec(string name1,char sex1,int age1){  //声明基类 Data_rec 
			name=name1;
			sex=sex1;
			age=age1;
		}
		void print(){
			cout<<"name:"<<name<<endl;
			cout<<"age:"<<age<<endl;
			cout<<"sex:"<<sex<<endl;
			
		}
};
class Student:virtual public Data_rec{		//声明类 Data_rec 是 Student 的虚基类 
	protected:
		string major;	//专业
		double score;	//成绩 
	public:
		Student(string name1,int age1,char sex1,string major1,double score1):Data_rec(name,sex,age){
			major=major1;
			score=score1;
		}
		void print(){
			Data_rec::print();
			cout<<"score:"<<score<<endl;
			cout<<"major:"<<major<<endl;
		}
};
class Employee:virtual public Data_rec{  //声明类 Data_rec 是 Employee 的虚基类 
	protected:
		string dept;	//部门
		double salary;	//酬金 
	public:
		Employee(string name1,char sex1,int age1,string dept1,double salary1):Data_rec(name1,sex1,age1){
			dept=dept1;
			salary=salary1;
		}
		void print(){
			Data_rec:print();
			cout<<"department:"<<dept<<endl;
			cout<<"salary:"<<salary<<endl;
		} 
};
class Teacher:public Employee{		//声明类 Teacher 为类 Employee 的派生类 
	protected:
		string title;	//职称
	public:
		Teacher(string name1,char sex1,int age1,string dept1,double salary1,string title1)
		:Data_rec(name1,sex1,age1),Employee(name1,sex1,age1,dept1,salary1){
			title=title1;
		}
		void print(){
			Employee::print();
			cout<<"title:"<<title<<endl;
		}
};
class E_Student:public Employee,public Student{		//声明类 E_Student 为类 Employee 和类 Student 的派生类 
	public:
		E_Student(string name1,char sex1,int age1,string major1,double score1,string dept1,double salary1):Data_rec(name1,sex1,age1),
		Student(name1,sex1,age1,major1,score1),Employee(name1,sex1,age1,dept1,salary1){
		}
		void print(){
			Student::print();
			cout<<"department:"<<dept<<endl;
			cout<<"salary:"<<salary<<endl;
		}
};
int main(){
	Student my_Student("小红",'f',22,"应用数学",90);
	cout<<"Student:"<<endl;
	my_Student.print();
	Employee my_Employee("小成",'m',23,"科研处",5000);
	cout<<"Employee:"<<endl;
	my_Employee.print();
	Teacher my_Teacher("小黄",'f',50,"管理学院",8000,"教授");
	cout<<"Teacher"<<endl;
	my_Teacher.print();
	E_Student my_E_Student("小吕",'m',34,"计算机",95,"教务处",3500);
	cout<<"E_Student:"<<endl;
	my_E_Student.print();
	return 0;
}