【C++ Primer Plus习题】11.5

news2024/12/25 0:21:40

问题:

解答:
main.cpp

#include <iostream>
#include "Stonewt.h"
using namespace std;

int main()
{
	Stonewt incognito = 275;
	cout << "incognito: " << incognito << endl;
	Stonewt wolfe(285.7);
	cout << "wolfe: " << wolfe <<endl;
	Stonewt taft(21, 8);
	cout << "taft: " << taft << endl;

	incognito = 276.8;
	cout << "incognito: " << incognito << endl;
	cout << "wolfe: " << wolfe*2.3 << endl;
	taft = incognito + wolfe + 200;
	cout << "taft: " << taft << endl;
	wolfe.setMode(Stonewt::FLOAT);
	wolfe = wolfe * 2.3;
	cout << "wolfe: " << wolfe * 2.3 << endl;

	return 0;
}

Stonewt.h

#pragma once
#include <iostream>
using namespace std;
class Stonewt
{
public:
	enum Mode { YIN, INT, FLOAT };
private:
	enum{Lbs_per_stn=14};
	int stone;
	double pds_left;
	double pounds;
	Mode mode;

public:
	Stonewt(double lbs);
	Stonewt(int stn, double lbs);
	Stonewt();
	~Stonewt();

	/*void show_lbs()const;
	void show_stn()const;*/

	void setMode(Mode m);
	Stonewt operator+(const Stonewt& s);
	Stonewt operator-(const Stonewt& s);
	Stonewt operator*(double n);

	friend ostream& operator<<(ostream& os, const Stonewt& s);
	friend Stonewt operator*(double m, Stonewt& s) { return s * m; }
};

Stonewt.cpp

#include "Stonewt.h"
#include <iostream>
using namespace std;

Stonewt::Stonewt(double lbs)
{
	stone = int(lbs) / Lbs_per_stn;
	pds_left = int(lbs) % Lbs_per_stn + lbs - int(lbs);
	pounds = lbs;
	mode = INT;
}
Stonewt::Stonewt(int stn, double lbs)
{
	stone = stn;
	pds_left = lbs;
	pounds = stn * Lbs_per_stn + lbs;
	mode = FLOAT;
}
Stonewt::Stonewt()
{
	stone = pounds = pds_left = 0;
	mode = YIN;
}
Stonewt::~Stonewt()
{

}

//void Stonewt::show_lbs()const
//{
//	cout << stone << " stone, " << pds_left << " pounds\n";
//}
//void Stonewt::show_stn()const
//{
//	cout << pounds << " pounds\n";
//}

void Stonewt::setMode(Mode m)
{
	this->mode = m;
}
Stonewt Stonewt::operator+(const Stonewt& s)
{
	Stonewt temp;
	temp.pounds = pounds + s.pounds;
	temp.stone = temp.pounds / Lbs_per_stn;
	temp.pds_left = int(temp.pounds) % Lbs_per_stn + temp.pounds - int(temp.pounds);
	temp.mode = this->mode;
	return temp;
}
Stonewt Stonewt::operator-(const Stonewt& s)
{
	Stonewt temp;
	temp.pounds = pounds - s.pounds;
	temp.stone = temp.pounds / Lbs_per_stn;
	temp.pds_left = int(temp.pounds) % Lbs_per_stn + temp.pounds - int(temp.pounds);
	temp.mode = this->mode;
	return temp;
}
Stonewt Stonewt::operator*(double n)
{
	Stonewt temp;
	temp.pounds = pounds *n;
	temp.stone = temp.pounds / Lbs_per_stn;
	temp.pds_left = int(temp.pounds) % Lbs_per_stn + temp.pounds - int(temp.pounds);
	temp.mode = this->mode;
	return temp;
}

ostream& operator<<(ostream& os, const Stonewt& s)
{
	if (s.mode == Stonewt::YIN)
	{
		double st = s.stone + s.pds_left / Stonewt::Lbs_per_stn;
		os << st << " stone\n";
	}
	if (s.mode == Stonewt::INT)
	{
		os << s.pounds << " pounds\n";
	}
	if (s.mode == Stonewt::FLOAT)
	{
		os << s.stone << " stone, " << s.pds_left << " pounds\n";
	}
	return os;
}