C++继承与派生（谭浩强11.8-11.10）

例11.8多重继承派生类的构造函数：

#include <iostream>
using namespace std;
#include<string>
class Teacher//声明基类
{
public://基类公用成员
	Teacher(string nam,int a,string t )//基类构造函数
	{
		name = nam;
		age=a;
		title = t;
	}
	void display()
	{
		cout << "name:" << name << endl;
		cout << "age:" <<age << endl;
		cout << "title:" << title << endl;
	}
protected://基类保护成员
	string name;
	int age;
	string title;
};
class Student //基类Student
{
public:
	Student(string nam,string s,float sco)
		//定义基类构造函数
	{
		name1= nam;
		sex = s;
		score = sco;
	}
	void display1()
	{
		cout << "name:" << name1 << endl;
		cout << "sex:" << sex << endl;
		cout << "score:" << score << endl;
	}
protected:
	string name1;
	string sex;
	float score;
};
class Graduate :public Teacher, public Student//声明多重继承派生类Graduate
{
public:
	Graduate(string nam, int a, string t, string s, float sco, float w)
		:Teacher(nam, a, t), Student(nam, s, sco)
	{
		wage = w;
	}
	//多重继承的构造函数
	void show()
	{
		cout << "name:" << name << endl;
		cout << "age:" << age << endl;
		cout << "title:" << title << endl;
		cout << "sex:" << sex << endl;
		cout << "score:" << score << endl;
		cout << "wages" << wage << endl;
	}
private:
	float wage;
};
int main()
{
	Graduate gradl("Wang-li",24,"f","assistant", 89.5,1200);
	gradl.show();
	return 0;
}

程序执行效果如图;

例11.9 虚基类的简单应用

#include <iostream>
using namespace std;
#include<string>
class Person
{
public://基类公用成员
	Person(string nam, string s, int a)//基类构造函数
	{
		name = nam;
		sex=s;
		age=a;
	}
protected://基类保护成员
	string name;
	string sex;
	int age;
};
class Teacher:virtual public Person//声明Person为公用继承的虚基类
{
public:
	Teacher(string nam,int a,string s,string t ):Person(nam,s,a)
		//构造函数
	{
		title = t;
	}
protected://保护成员
	string title;
};
class Student:virtual public Person //用public方式声明派生类Student1
{
public:
	Student(string nam, string s, int a, float sco) :
		Person(nam, s, a), score(sco){}//初始化表构造函数
protected:

	float score;
};
class Graduate :public Teacher, public Student//声明多重继承派生类Graduate
{
public:
	Graduate(string nam, int a, string t, string s, float sco, float w)
		:Person(nam, s, a), Teacher(nam,a, s, t), Student(nam, s, a, sco),
		wage(w){}
	//多重继承的构造函数初始化表
	void show()
	{
		cout << "name:" << name << endl;
		cout << "age:" << age << endl;
		cout << "title:" << title << endl;
		cout << "sex:" << sex << endl;
		cout << "score:" << score << endl;
		cout << "wages" << wage << endl;
	}
private:
	float wage;
};
int main()
{
	Graduate gradl("Wang-li",24,"f","assistant", 89.5,1200);
	gradl.show();
	return 0;
}

程序执行结果如图：

例111.10，用指向基类的指针输出派生类数据：

#include <iostream>
using namespace std;
#include<string>
class Student
{
public:
	Student(int, string, float);
	void display();
private:
	int num;
	string name;
	float score;
};
Student::Student(int n, string nam, float s)
//类外定义构造函数需要指明作用域
{
	num = n;
	name = nam;
	score = s; }
void Student::display()
{
	cout << endl<< "num:" << num << endl;
	cout << "name:" << name << endl;
	cout << "score:" << score << endl;
}
class Graduate :public Student//声明公用派生类Graduate
{public:
	Graduate(int, string, float, float);
	void display();
private:
	float wage;
};
Graduate::Graduate(int n, string nam, float s, float w)
//类外定义构造函数需要指明作用域
		: Student(n, nam, s), wage(w){}
	//定义构造函数多重继承的构造函数初始化表
	void Graduate::display()
	{
		Student::display();
		cout << "wages=" << wage << endl;
	}
int main()
{
	Student stud1(1001, "Li", 87.5);
	Graduate gradl(2001,"wang", 89.5,1000);
	Student *pt = &stud1;//定义指向基类Student对象的指针
	pt->display();
	pt = &gradl;/*指针指向派生类Graduate的对象gradl,但是该指针只能访问派生类中的基类成员,而不能访问派生类中新增加的成员，要想访问派生类新增成员可以使用虚函数*/
	pt->display();
	return 0;
}

程序执行效果如图：