7장 실습문제_1번

1. Book 객체에 대해 다음 연산을 하고자 한다.

Book a("청춘", 20000, 300), b("미래", 30000, 500);
a += 500;
b -= 500;
a.show();
b.show();

Book 클래스는 다음과 같다.

class Book {
	string title;
	int price, pages;
public:
	Book(string title = "", int price = 0, int pages = 0) {
		this->title = title;
		this->price = price;
		this->pages = pages;
	}
	void show() {
		cout << title << ' ' << price << "원" << pages << "페이지" << endl;
	}
	string getTitle() { return title; }
};

(1) +=,-=연산자 함수를 Book 클래스의 멤버함수로 구현하라.

(2) +=,-=연산자 함수를 Book 클래스의 외부함수로 구현하라.

 

 

 

-답

(1)

#include <iostream>
using namespace std;

class Book {
	string title;
	int price, pages;
public:
	Book(string title = "", int price = 0, int pages = 0) {
		this->title = title;
		this->price = price;
		this->pages = pages;
	}
	void show() {
		cout << title << ' ' << price << "원" << pages << "페이지" << endl;
	}
	string getTitle() { return title; }
	void operator+= (int x) { price += x; }
	void operator-=(int x) { price -= x; }
};


int main() {
	Book a("청춘", 20000, 300), b("미래", 30000, 500);
	a += 500;
	b -= 500;
	a.show();
	b.show();
}

(2)

#include <iostream>
using namespace std;

class Book {
	string title;
	int price, pages;
public:
	Book(string title = "", int price = 0, int pages = 0) {
		this->title = title;
		this->price = price;
		this->pages = pages;
	}
	void show() {
		cout << title << ' ' << price << "원" << pages << "페이지" << endl;
	}
	string getTitle() { return title; }
	friend Book operator+=(Book &op,int x);
	friend Book operator-=(Book &op,int x);
};

Book operator+=(Book &op,int x) {
	op.price += x;
	return op;
}

Book operator-=(Book& op, int x) {
	op.price -= x;
	return op;
}

int main() {
	Book a("청춘", 20000, 300), b("미래", 30000, 500);
	a += 500;
	b -= 500;
	a.show();
	b.show();
}