ep4_4.cpp

这里有大量的c语言习题呢！真的是题海哦

/* 4.4 设计并测试一个矩形类（Rectangle），属性为矩形的左下与右上角的坐标，矩形水平放置。
操作为计算矩形周长与面积。测试包括用成员函数和普通函数。*/

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

class Rectangle {
	double left, top ;
	double right, bottom;
public:
	Rectangle(double l=0, double t=0, double r=0, double b=0);
	~ Rectangle(){};  //析构函数，在此函数体为空
	void Assign(double l,double t,double r,double b);
	double getLeft(){ return left;} // 以下四个函数皆为内联成员函数
	double getRight(){ return right;}
	double getTop(){return top;}
	double getBottom(){return bottom;}
	void Show();
	double Area();
	double Perimeter();
};

// 构造函数，带缺省参数，缺省值为全0，在声明中指定
Rectangle::Rectangle(double l , double t, double r, double b) {
	left = l; top = t;
	right = r; bottom = b; 
}
void Rectangle::Assign(double l, double t, double r, double b){//赋值
	left = l; top = t;
	right = r; bottom = b;
}
void Rectangle::Show(){//成员函数直接使用私有的数据成员
	cout<<"left-top point is ("<<left<<","<<top<<")"<<'\n';
	cout<<"right-bottom point is ("<<right<<","<<bottom<<")"<<'\n';
}
double Rectangle::Area(){
	return fabs((right-left)*(bottom-top));
}
double Rectangle::Perimeter(){
	return 2*(fabs(right-left)+fabs(bottom-top));
}

int main(){
	Rectangle rect; 
	rect.Show();
	rect.Assign(100,200,300,400);
	rect.Show();
	Rectangle rect1(0,0,200,200);
	rect1.Show();
	Rectangle rect2(rect1);
	rect2.Show();
	cout<<"面积"<<rect.Area()<<'\t'<<"周长"<<rect.Perimeter()<<endl;
	return 0;
}