c++示例代码-静态数据成员

[code]#include <iostream>
using namespace std;
class Point
{public:
Point(int xx=0, int yy=0)
{X=xx; Y=yy; countP++; }
Point(Point &p);
int GetX(){return X;}
int GetY(){return Y;}
void GetC(){cout<<" Object id="<<countP<<endl;}
private:
int X,Y;
static int countP;
};

Point::Point(Point &p)
{	X=p.X;
Y=p.Y;
countP++;
}

int Point::countP=0;
int main()
{	Point A(4,5);
cout<<"Point A,"<<A.GetX()<<","<<A.GetY();
A.GetC();
Point B(A);
cout<<"Point B,"<<B.GetX()<<","<<B.GetY();
B.GetC();
}

[code]#include<iostream.h>
class Application
{ public:
static void f();
static void g();
private:
static int global;
};
int
Application::global=0;

void Application::f()
{ global=5;}
void Application::g()
{cout<<global<<endl;}

int main()
{
Application::f();
Application::g();
return 0;
}

[code]class A
{
public:
static void f(A a);
private:
int x;
};
void A::f(A a)
{
cout<<x; //对x的引用是错误的
cout<<a.x;  //正确
}

#include <iostream.h>
class Point	//Point类声明
{public:	//外部接口
Point(int xx=0,int yy=0){X=xx;Y=yy;countP++;}
Point(Point &p);//拷贝构造函数
int GetX() {return X;}
int GetY() {return Y;}
static void GetC()
{cout<<" Object id="<<countP<<endl;}
private: //私有数据成员
int X,Y;
static int countP;
}

Point::Point(Point &p)
{	X=p.X;
Y=p.Y;
countP++;
}
int Point::countP=0;
int main()	//主函数实现
{	Point A(4,5);	//声明对象A
cout<<"Point A,"<<A.GetX()<<","<<A.GetY();
A.GetC();	//输出对象号，对象名引用
Point B(A);	//声明对象B
cout<<"Point B,"<<B.GetX()<<","<<B.GetY();
Point::GetC();	//输出对象号，类名引用
}