#pragma once
#ifndef CD_H_
#define CD_H_
//base classclass Cd
{
private:char * performers;char * label;int selection;    //number of selectiondouble playtime;
public:Cd();Cd(const Cd & d);Cd(char * s1, char * s2, int n, double x);virtual ~Cd();virtual void Report() const;    //reports all cd dataCd & operator= (const Cd & d);
};
#endif // !CD_H_
#pragma once

#pragma once
#ifndef CLASSIC_H_
#define CLASSIC_H_
#include"CD.h"class Classic : public Cd
{
private:char * mainprod;
public:Classic();Classic(char * s1, char * s2, char * s3, int n, double x);Classic(const Classic & a);~Classic();Classic & operator=(const Classic & a);void Report() const;
};#endif // !CLASSIC_H_

#include"classic.h"
#include<cstring>
#include<iostream>
using std::strcpy;
using std::strlen;
using std::cout;
using std::endl;
//base cd

Cd::Cd()
{performers = new char[1];performers[0] = '\0';label = new char[1];label[0] = '\0';    //构造函数保持统一格式对应析构函数selection = 0;playtime = 0.0;
}Cd::Cd(const Cd & a)
{int len;len = strlen(a.performers);performers = new char[len + 1];strcpy(performers, a.performers);len = strlen(a.label);label = new char[len + 1];strcpy(label, a.label);selection = a.selection;playtime = a.playtime;
}Cd & Cd::operator=(const Cd & a)
{//记住第一步要先delete掉以前的，节省内存delete[]performers;delete[]label;int len;len = strlen(a.performers);performers = new char[len + 1];strcpy(performers, a.performers);len = strlen(a.label);label = new char[len + 1];strcpy(label, a.label);selection = a.selection;playtime = a.playtime;return *this;
}Cd::Cd(char * s1, char * s2, int n, double x)
{int len;len = strlen(s1);performers = new char[len + 1];    //记得要加一,strlen不算‘\0’
    strcpy(performers, s1);len = strlen(s2);label = new char[len + 1];strcpy(label, s2);selection = n;playtime = x;
}Cd::~Cd()
{delete[]performers;delete[]label;
}void Cd::Report() const
{cout << "performers: " << performers << endl;cout << " label: " << label << endl;cout << " selection: " << selection << endl;cout << " playtime: " << playtime << endl;
}Classic::~Classic()
{//Cd::~Cd;//这句不用，写了报错，重复删除delete[]mainprod;//派生析构只用删除派生类里的新成员就好
}Classic::Classic() : Cd()
{mainprod = new char[1];mainprod[0] = '\0';    //构造函数要统一型式以兼容析构函数
}Classic::Classic(char * s1, char * s2, char * s3, int a, double x) : Cd(s1, s2, a, x)
{int len;len = strlen(s3);mainprod = new char[len + 1];strcpy(mainprod, s3);
}Classic::Classic(const Classic & a) : Cd(a)
{int len;len = strlen(a.mainprod);mainprod = new char[len + 1];strcpy(mainprod, a.mainprod);
}Classic & Classic::operator=(const Classic & a)
{//先要用基类的重载= 给基类部分赋值Cd::operator=(a);delete[]mainprod;int len;len = strlen(a.mainprod);mainprod = new char[len + 1];strcpy(mainprod, a.mainprod);//别忘记要返回值return *this;
}void Classic::Report() const
{Cd::Report();cout << " mainproduction: " << mainprod << endl;
}

#include<iostream>
using namespace std;
#include"classic.h"    //will contain #include cd.h
void Bravo(const Cd & disk);
//记住要自己修改cd.h文件
int main()
{Cd c1("Beatles", "Capitol", 14, 35.5);Classic  c2 = Classic("Piano Sonata in B flat, Fantasia in C", "Alfred Brendel", "Philios", 2, 57.17);Cd * pcd = &c1;cout << "using object directly:\n";c1.Report();c2.Report();//Cd sd;
cout << "using type cd * pointer to object:\n";pcd->Report();pcd = &c2;pcd->Report();cout << "Calling a function with a Cd reference argument:\n";Bravo(c1);Bravo(c2);cout << "testing assignment" << endl;Classic copy;copy = c2;copy.Report();return 0;
}void Bravo(const Cd & disk)
{disk.Report();
}