C++Primer Plus（第六版） 第十三章 第一题

classic.h

// base class
// #pragma once
#ifndef CLASSIC_H_
#define CLASSIC_H_
class Cd { // represents a CD disk
private:
	char performers[50];
	char label[20];
	int selections; // number of selections
	double playtime; // playing time in minutes
public:
	Cd(char * s1 = "", char * s2 = "", int n = 0, double x = 0.0);
	Cd(const Cd & d);
	~Cd();
	virtual void Report() const; // reports all CD data
	Cd & operator=(const Cd & d);
};
class Classic :public Cd
{
private:
	char songs[80];
public:
	Classic(const char * sg = "", char * s1 = "", char * s2 = "", int n = 0, double x = 0.0);
	~Classic();
	virtual void Report() const;
	Classic & operator=(const Classic &cl);
};
#endif // !CLASSIC_H_

classic.cpp

#include "classic.h"
#include <iostream>

Cd::Cd(char * s1, char * s2, int n, double x)
{
	std::strncpy(performers, s1, 50);
	std::strncpy(label, s2, 20);
	selections = n;
	playtime = x;
}

Cd::Cd(const Cd & d)
{
	std::strncpy(performers, d.performers, 50);
	std::strncpy(label, d.label, 20);
	selections = d.selections;
	playtime = d.playtime;
}

Cd::~Cd()
{
}

void Cd::Report() const
{
	std::cout << "Performers: " << performers << std::endl;
	std::cout << "Label: " << label << std::endl;
	std::cout << "Selections: " << selections << std::endl;
	std::cout << "Playtime: " << playtime << std::endl;
}

Cd & Cd::operator=(const Cd & d)
{
	if (this == &d)
		return *this;
	std::strncpy(performers, d.performers, 50);
	std::strncpy(label, d.label, 20);
	selections = d.selections;
	playtime = d.playtime;
	return *this;
}

Classic::Classic(const char * sg, char * s1, char * s2, int n, double x) :Cd(s1, s2, n, x)
{
	std::strncpy(songs, sg, 80);
}

Classic::~Classic()
{
}

void Classic::Report() const
{
	Cd::Report();
	std::cout << "Songs: " << songs << std::endl;
}

Classic & Classic::operator=(const Classic & cl)
{
	if (this == &cl)
		return *this;
	Cd::operator=(cl);
	std::strncpy(songs, cl.songs, 80);
	return *this;
}

main.cpp

#include <iostream>
using namespace std;
#include "classic.h"	// which will contain #include cd.h
void Bravo(const Cd & disk);
int main()
{
	Cd cl("Beatles", "CapitoPV", 14, 35.5);
	Classic c2 = Classic("Piano Sonata in-B flat, Fantasia in-C",
		"Alfred Brendel", "Philips", 2, 57.17);
	Cd *pcd = &cl;

	cout << "Using obfectr directly:\n";
	cl.Report(); // use Cd method
	c2.Report(); // use Classic method

	cout << "Using type cd * pointer to objects:\n";
	pcd->Report(); // use Cd method for cd object
	pcd = &c2;
	pcd->Report();	// use Classic method for classic object

	cout << "Calling, a function with a Cd reference argument:\n";
	Bravo(cl);
	Bravo(c2);

	cout << "Testing assignment: ";
	Classic copy;
	copy = c2;
	copy.Report();

	cin.get();
	return 0;
}

void Bravo(const Cd & disk)
{
	disk.Report();
}