设计并测试一个名为Rectangle的矩形类，其属性为矩形的左下角与右上角两个点的坐标，能计算矩形的面积

给你两种 写法
第一种：
#include <iostream.h>
#include <math.h>

class rectangle
{
public:
 rectangle(int left,int bottom,int right,int top);
 ~rectangle(){ }
 //int getleft() {return itsleft;}
 int getbottom() {return itsbottom;}
 int getright() {return itsright;}
 int gettop() { return itstop;}

 void setleft(int left) {itsleft=left;}
 void setbottom(int bottom) {itsbottom=bottom;}
 void setright(int right) {itsright=right;}
 void settop(int top) {itstop=top;}

 int getarea();
private:
 int itsleft;
 int itsbottom;
 int itsright;
 int itstop;
int width;
int height;
};
rectangle::rectangle(int left,int bottom,int right,int top)
{
 itsleft=left;
 itsbottom=bottom;
 itsright=right;
 itstop=top;
}

int rectangle::getarea()
{
 width=abs(itsright-itsleft);
 height=abs(itstop-itsbottom);
 cout<<"该矩形的长："<<width<<endl;
 cout<<"该矩形的宽："<<height<<endl;
 return (width*height);
}

void main()
{
 rectangle myrectangle(20,20,60,50);
 int area;
 area=myrectangle.getarea();
 cout<<"area:"<<area<<endl;
 myrectangle.setleft(10);
 area=myrectangle.getarea();
 cout<<"area:"<<area<<endl;
}

第二种 ：
#include<iostream.h>
#include<math.h>
class rectangle
{
private:
 int left;
 int bottom;
 int right;
 int top;
public:
 void setpoint(int l,int b,int r,int t)
 {
 left=l;
 bottom=b;
 right=r;
 top=t;
 }
 void cal(int left,int bottom,int right,int top)
 {
 int s;
 s=abs(left-right)*abs(bottom-top);
 cout<<"该长方形的面积为："<<s<<endl;
 }
 void getp1(int left,int bottom)
 {
 cout<<"长方形的左下角坐标是："<<left<<","<<bottom<<endl;
 }
 void getp2(int right,int top)
 {
 cout<<"长方形的右上角坐标是："<<right<<","<<top<<endl;
 }
};

void main()
{ 
 rectangle r1;
 int l,b,r,t;
 cout<<"请输入长方形的左下角的坐标：";
 cin>>l>>b;
 cout<<"请输入长方形的右上角的坐标：";
 cin>>r>>t;
 r1.getp1(l,b);
 r1.getp2(r,t);
 r1.cal(l,b,r,t);
}