3-4 计算长方形的周长和面积

Time Limit: 1000MS  Memory Limit: 65536KB

​​Submit​​​  ​​​Statistic​​

Problem Description

通过本题的练习可以掌握拷贝构造函数的定义和使用方法；

设计一个长方形类Rect，计算长方形的周长与面积。类中有私有数据成员Length(长)、Width(宽)，由具有缺省参数值的构造函数对其初始化，函数原型为：Rect(double Length=0, double Width=0); 再为其定义拷贝构造函数，形参为对象的常引用，函数原型为：Rect(const Rect &); 编写主函数，创建Rect对象r1初始化为长、宽数据，利用r1初始化另一个Rect对象r2，分别输出对象的长和宽、周长和面积。

要求： 创建对象 Rect r1(3.0,2.0),r2(r1);

Input

输入两个实数，中间用一个空格间隔；代表长方形的长和宽

Output

共有6行 ；
分别输出r1的长和宽； r1的周长； r1的面积；r2的长和宽； r2的周长； r2的面积；注意单词与单词之间用一个空格间隔

Example Input

56 32

Example Output

the length and width of r1 is:56,32 the perimeter of r1 is:176 the area of r1 is:1792 the length and width of r2 is:56,32 the perimeter of r2 is:176 the area of r2 is:1792

Hint

输入 -7.0 -8.0

输出

the length and width of r1 is:0,0

the perimeter of r1 is:0

the area of r1 is:0

the length and width of r2 is:0,0

the perimeter of r2 is:0

the area of r2 is:0

#include <iostream>
using namespace std;
class Rect
{
private:
double length;
double width;
public:
Rect(double x=0,double y =0)
{
        length = x;
width = y;
}
Rect(const Rect &b)
{
length = b.length;
width = b.width;
}
const void display()
{
cout << "the length and width of r1 is:" << length << ","<< width << endl;
        cout << "the perimeter of r1 is:" << (length + width) * 2<<endl;
        cout << "the area of r1 is:" << length * width << endl;
}
void display1()
{
cout << "the length and width of r2 is:" << length << ',' << width<< endl;
        cout << "the perimeter of r2 is:" << (length + width) * 2 << endl;
        cout << "the area of r2 is:" << length * width << endl;
}

};


int main()
{
double x,y;
cin>>x>>y;
if(x<0||y<0)
{
x=0;
y=0;
}
Rect r1(x,y);
Rect r2 = r1;
r1.display();
r2.display1();
return 0;
}