继承与派生类 学习笔记2

派生类的构造函数与析构函数

注意：派生类是不能继承基类的构造函数和析构函数的。对于派生类的构造函数，由于派生类不能直接访问基类的私有成员，只能通过基类的方法进行访问，所以派生类构造函数必须使用基类的构造函数。

派生类需要析构函数完成一些必要的清理工作，必须定义自己的的析构函数。

头函数：

#ifndef INHERIT_H_#define INHERIT_H_const int READY=0;const int RUNNING=1;class Car{private:int status;public:Car(int s=READY);void StartCar();void StopCar();int GetStatus();};class FireCar:public Car{private:char way[10];public:FireCar(char* c="water",int s=READY);void PutFire(); //增加的方法};#endif

方法：

#include<iostream>#include<cstring>#include"Inherit.h"using namespace std;Car::Car(int s){status=s;}void Car::StartCar(){status=RUNNING;cout << "the car is running." << endl;}void Car::StopCar(){status=READY;cout << "the car is stopped." << endl;}int Car::GetStatus(){return status;}FireCar::FireCar(char* c,int s):Car(s){strcpy(way,c);}void FireCar::PutFire(){if(GetStatus()==RUNNING)cout << "this FireCar uses" << way<< "to put out the fire." << endl;elsecout << "Can't use a unusing FireCar to put out a fire." << endl;}

主函数：

#include<iostream>#include"Inherit.h"using namespace std;int main(){FireCar fc1;FireCar fc2("DryIce",RUNNING);cout << "For FireCar1:" << endl;fc1.PutFire();fc1.StartCar();fc1.PutFire();cout << endl;cout << "For FireCar2:" <<endl;fc2.PutFire();return 0;}

运行结果：

 

多重继承

代码：

//Multiin.h#ifndef MULTIIN_H_#define MULTIIN_H_class Student{private:int Number;char academy[20];public:Student(int n=1,char* aca="Sichuang University");int GetNumber() const{return Number;}char* GetAcad(){return academy;}};class Player{private:char event[20];public:Player(char* ev="football");char * GetEvent(){return event;}};class StuPlayer:public Student,public Player{private:char Name[10];public:StuPlayer(char* n="John",char* a="Sichuan University",int i=1,char* e="football");void ShowMe();};#endif

//Mltiin.cpp#include<iostream>#include<cstring>#include"Multiin.h"using namespace std;Student::Student(int n,char* aca){Number=n;strcpy(academy,aca);}Player::Player(char* ev){strcpy(event,ev);}StuPlayer::StuPlayer(char* n,char* a,int i,char* e):Student(i,a),Player(e){strcpy(Name,n);}void StuPlayer::ShowMe(){cout << "My name is" << Name << endl;cout << "I am a student in" << GetAcad() << endl;cout << "I am also a player. I play" << GetEvent() << endl;}

//usemult.cpp#include<iostream>#include"Multiin.h"using namespace std;int main(){StuPlayer st1;StuPlayer st2("Emily","Wuhan University",8,"basketball");cout << "For student player 1:" << endl;st1.ShowMe();cout << endl;cout << "For student player 2:" << endl;st2.ShowMe();return 0;}

结果：