3-4 计算长方形的周长和面积

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

代码如下：

#include<iostream>

using namespace std;

class Rect
{
private:
double length, width;
public:
Rect(double x = 0, double y = 0)
{
length = x;
width = y;
}
Rect(Rect &b)
{
length = b.length;
width = b.width;
}
void Show()
{
cout << "the length and width of r1 is:" << length << "," << width << endl;
cout << "the perimeter of r1 is:" << 2 * (length + width) << endl;
cout << "the area of r1 is:" << length*width << endl;
}
void Show1()
{
cout << "the length and width of r2 is:" << length << "," << width << endl;
cout << "the perimeter of r2 is:" << 2 * (length + width) << 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.Show();
r2.Show1();
return 0;
}