C++primer plus第六版课后编程练习答案13.4

#include <iostream>  
#include <string>  
//我懒得用char*了  
using namespace std;  
class Port{  
protected:  //懒得用方法了，就直接保护吧
    string brand;  
    //string style;//不需要style，因为派生出来的就是style  
    int bottles;  
public:  
    string getbr()const{return brand;};  
    int getbot()const{return bottles;};  
    Port(const string br="none",int b=0)//const string st="none"  
    {  
        brand=br;  
        //style=st;  
        bottles=b;  
    }  
    Port(const Port &p)  
    {  
        brand=p.brand;  
        //style=p.style;  
        bottles=p.bottles;            
    }  
    //Port(){};//因为派生类无参数的构造函数，所以基类必须有相对应的构造函数  
    //发现不用也是可以的，因为第一个有了默认参数值，也可以算是无参构造函数  
  
    virtual ~Port(){}  
    Port &operator=(const Port &p)  
    {  
  //    return Port(p);//不能使用类似:Port p;p=p2,这种情况，必须声明的同时赋值  
		if(this==&p)
			return *this;
		brand=p.brand;
		bottles=p.bottles;
		return *this;
    }  
    Port &operator+=(int b)  
    {  
        bottles=bottles+b;  
        return *this;  
    }  
    Port &operator-=(int b)  
    {  
        if(bottles>=b)  
            bottles=bottles-b;  
        else  
            cout<<"error！no so much brand!"<<endl;  
        return *this;  
    }  
    int BottlesCount()const{return bottles;};  
    virtual void Show()const  
    {  
        cout<<"Brand:"<<brand<<endl;  
        //cout<<"Kind:"<<style<<endl;  
        cout<<"Bottlse："<<bottles<<endl;  
    }  
    friend ostream &operator<<(ostream &os,const Port &p)  
    {  
        cout<<p.brand<<" ,"<<p.bottles<<endl;  
        return os;  
    }  
};  
class VintagePort:public Port  
{  
private:  
    string nickname;  
    int year;  
public:  
    VintagePort(){  
        Port::Port();  
        nickname="default";  
        year=2999;  
    };  
    VintagePort(const string br,int b,const string nn,int y=2999):Port(br,b)  
    {  
        nickname=nn;  
        year=y;  
    };  
    VintagePort(const VintagePort &vp)  
    {  
		brand=vp.brand;  
        //style=p.style;  
        bottles=vp.bottles;   
        nickname=vp.nickname;  
        year=vp.year;  
    }  
    ~VintagePort(){};  
    VintagePort &operator=(const VintagePort &vp)  
    {  
     // return VintagePort(vp);   //使用这种方法调用的是使用此赋值运算符的构造函数，当此对象构造过后，此赋值运算符将无效
		if(this==&vp)
			return *this;
		brand=vp.brand;
		bottles=vp.bottles;
		nickname=vp.nickname;
		year=vp.year;
		return *this;
    }  
    void Show()  
    {  
        Port::Show();  
        cout<<"nickname:"<<nickname<<endl;  
        cout<<"year:"<<year<<endl;  
    }  
    friend ostream &operator<<(ostream &os,const VintagePort &p)  
    {  
  
        os<<(const Port &)p;  
        cout<<p.nickname<<" ,"<<p.year<<endl;  
        return os;  
    }  
};  

#include <iostream>  
#include "Port.cpp"  
using namespace std;  
  
void main()  
{  
    Port p1("Gallo",20); 
    Port p2(p1); 
    Port p3;//=p1; 
    //p3=p1;//这时候，p3已经采取了默认初始化值 
    //p1.Show(); 
    //cout<<p1; 
    //cout<<p3; 
    p2.Show(); 
    p2+=10; 
    p2.Show(); 
    p2-=15; 
    p2.Show(); 
     
  
    VintagePort vp1;  
    //vp1.Show();  
    VintagePort vp2("Vintage",140,"xxoo",1989);  
    //vp2.Show();  
    cout<<vp2;  
    VintagePort vp3(vp2);  
   // VintagePort vp3("Vin",14,"xo",19);
	vp3.Show();
//	VintagePort vp3;
	//vp3=vp2;
    vp3.Show();  
  
  
  
  
    cin.get();  
    cin.get();  
  
  
}