3-4 计算长方形的周长和面积
Time Limit: 1000MS
Memory Limit: 65536KB
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
Author
#include<bits/stdc++.h>
using namespace std;
class Rect
{
public:
Rect(double l = 0, double w = 0)//构造函数
{
len = l;
wid = w;
}
Rect(const Rect &R)//复制构造函数
{
len = R.len;
wid = R.wid;
}
const void put()
{
cout << "the length and width of r1 is:" << len << ","<< wid << endl;
cout << "the perimeter of r1 is:" << (len + wid) * 2<<endl;
cout << "the area of r1 is:" << len * wid << endl;
}
const void put1()
{
cout << "the length and width of r2 is:" << len << ',' << wid<< endl;
cout << "the perimeter of r2 is:" << (len + wid) * 2 << endl;
cout << "the area of r2 is:" << len * wid << endl;
}
private:
double len;
double wid;
};
int main()
{
double x, y;
cin>>x>>y;
if(x < 0 || y < 0)
{
x = 0;
y = 0;
}//需要考虑的情况,不加就是Wrong
Rect rect(x,y);
Rect rect1(rect);//或者写成 Rect rect1 = rect;意义都是用rect初始化rect1
rect.put();
rect1.put1();
return 0;
}