©TCP-tryC++

#include <iostream>
#include <cmath>
using namespace std;

class Rect;

class Display
{
public:
	void ShowSize(const Rect& target);
	void ShowDiagonal(const Rect& target);
};

class Rect
{
private:
	double height_;
	double width_;
public:
	Rect(double height, double width);	// 생성자 
	void height() const;
	void width() const;
	friend void Display::ShowDiagonal(const Rect& target);	// 프렌드 멤버 함수 선언 
};

int main(void)
{
	Rect rect01(10, 20);
	
	Display rect_display;
	rect_display.ShowSize(rect01);
	rect_display.ShowDiagonal(rect01);
	
	return 0;
}

Rect::Rect(double height, double width)
{
	height_ = height;
	width_ = width;
}

void Rect::height() const
{
	cout << "이 사각형의 높이는 " << this->height_ << "입니다." << endl;
}

void Rect::width() const
{
	cout << "이 사각형의 너비는 " << this->width_ << "입니다." << endl;
}

void Display::ShowSize(const Rect& target)
{
	target.height();
	target.width();
}

void Display::ShowDiagonal(const Rect& target)
{
	double diagonal;
	diagonal = sqrt(pow(target.height_, 2) + pow(target.width_, 2));
	
	cout << "이 사각형의 대각선의 길이는 " << diagonal << "입니다." << endl;
}