demo_operator_04_b.cpp

对于一个初涉VC＋＋的人来书

//************************************************

# include <iostream.h>

class Increase
{
public:
	Increase(int x):value(x){}
	friend Increase & operator ++(Increase &);   //前增量
	friend Increase operator ++(Increase &,int); //后增量
	void display() { cout<<"The value is: "<<value<<endl; }
private:
	int value;
};

Increase & operator ++(Increase & s) //前增量返回引用
{
	++s.value; //先增量
	return s;  //再返回原对象
}

Increase operator ++(Increase & s,int) //后增量返回值
{
	Increase temp(s); //通过拷贝构造函数保存原有对象值
	s.value++;        //原有对象增量修改
	return temp;      //返回原有对象值
}

void main()
{
	Increase n(20);

	n.display();
	(n++).display();
	n.display();

	++n;
	n.display();
	++(++n);
	n.display();

	(n++)++;
	n.display();
}