//**********************
//**    ch18_5.cpp    **
//**********************

#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 & a)
{
  a.value++;                           //前增量
  return a;                            //再返回原對象
}

Increase operator++(Increase& a, int)
{
  Increase temp(a);                //通過拷貝構造函數保存原有對象值
  a.value++;                       //原有對象增量修改
  return temp;                     //返回原有對象值
}

void main()
{
  Increase n(20);
  n.display();
  (n++).display();                 //顯示臨時對象值
  n.display();                     //顯示原有對象
  ++n;
  n.display();
  ++(++n);
  n.display();

  (n++)++;                         //第二次增量操作對臨時對象進行
  n.display();
  cin.get();
}