513ok.cpp

C++实训教程

//513ok.CPP  Ok with Copy constructor
#include <iostream.h>
#include <conio.h>
class Car
{
		float price;
		static int Num;// private静态成员变量
	public:
		Car(){price=0;Num++;};
		Car(float pp){price=pp;Num++;};
		Car(Car & r){price=r.price; Num++;}
		~Car(){Num--;};
		static int GetNum(){return Num;};
};
void fn(Car c);
int Car::Num=0;// 对静态公有成员变量进行初始化

void main()
{
	Car r1(20.0);
	cout<<"Num of Cars is "<<Car::GetNum()<<".\n";
	fn(r1);
	cout<<"Num of Cars is "<<Car::GetNum()<<".\n";
}
void fn(Car c)
{
	Car o1=c;
	Car o2(100);
	Car o3=o2;
	cout<<"Num of Cars is "<<Car::GetNum()<<".\n";
}
	
/*
Num of Cars is 1.
Num of Cars is 5.
Num of Cars is 1.


*/