静态数据成员与子对象

1、/*定义一个圆类，声明一个静态数据成员和一个静态成员函数，静态数据成员表示圆的个数，定义对象时个数加1，西狗屎个数减1，静态成员函数显示静态数据成员的值*/#include <iostream>using namespace std;class Circlepublic:Circle(float tr) r=tr ;countP+; Circle(Circle &p)r=p.r;countP+; static void GetP( ) cout<<" circle num="<<countP<<endl; Circle

2、()countP-; private:int r;static int countP;int Circle:countP=0; /给静态数据成员countP初始化void main( )Circle A(4); A.GetP(); /*模拟商店一种货物的购进和卖出情况，要求该种货物以重量为单位成箱买卖，每箱的重量不相同，并且要求记录目前库存总重量和总价格。*/#include <iostream>using namespace std;class Goodspublic:Goods(float tprice,float tweight) unitPrice=tprice ; wei

3、ght=tweight;sumPrice+=unitPrice*weight;sumWeight+=weight;selFlag=0; void sell() selFlag=1; sumWeight-=weight;sumPrice-=unitPrice*weight;static void Show( )cout<<" sumPrice="<<sumPrice<<endl<<" sumWeight="<<sumWeight<<endl; private:float unitPri

4、ce,weight,selFlag;static float sumPrice,sumWeight;float Goods:sumPrice =0;float Goods:sumWeight=0; void main( )Goods A(4,5); A.Show (); A.sell ();A.Show(); /定义点类，并用两个点构成一个矩形，求矩形的面积和周长#include<iostream>#include<cmath>using namespace std;class Point/Point类定义public:Point(int xx=0, int yy=0)

5、 X=xx;Y=yy;Point(Point &p);int GetX() return X;int GetY() return Y;friend class Rectangle;private:int X,Y;Point:Point(Point &p)/拷贝构造函数的实现X=p.X;Y=p.Y;/类的聚集class Rectangle/Distance类的定义public:/外部接口Rectangle(Point xp1, Point xp2);Rectangle(int x1,int y1,int x2,int y2);double Area() return length

6、*width;double RoundLength()return 2*(length+width);private:/私有数据成员Point p1,p2;/Point类的对象p1,p2double length,width;Rectangle:Rectangle(Point xp1, Point xp2):p1(xp1),p2(xp2) /类的聚集的构造函数length=abs(p1.X-p2.X);width=abs(p1.Y -p2.Y);Rectangle:Rectangle(int x1,int y1,int x2,int y2):p1(x1,y1),p2(x2,y2) length=abs(p1.X-p2.X);width=abs(p1.Y -p2.Y);/主函数void main()int x1,x2,y1,y2;cin>>x1>>y1>>x2>>y2;Point myp1(x1,y1),myp2(x2,y2);/定义Point类的对象Rectangle r1(myp1,myp2);/定义Distance类的对象cout<<"The Rectangel's area is: "<<r1.Area()<<endl; R