502.cpp

C++实训教程

/*
	502.cpp
	demo  static member
	By F. 2003 Oct
*/	
#include <iostream.h>
void f();
class G  //Goods
{
  private:
	 static int totalW;
    int w;  //weight
  public:
	G(int a=100)
	{ w = a;   totalW += w; }
	int Get(){return w;}
	static int  GetTotalW(void)	{return totalW;}
	~G(){totalW -= w; }
};

int G::totalW = 0;  //must be!

main()
{
	G g1,g2(12);	//declare G object
	cout << "The Total is:" << G::GetTotalW() << endl;
    f();
	cout << "The Total is:" << G::GetTotalW() << endl;
	return 0;
}

void f()
{
	G g3(20);
	cout << "The Total is:" << G::GetTotalW() << endl;
}
/*ok output  on screen ,while running:
The Total is:112
The Total is:132
The Total is:112
*/