求助：运算符重载的。。

补充一下全部程序:程序的功能是设计一个记数器累 Calculator ，实现前后自增自减和相加减。。。#include <iostream.h>
class Calculator
{
private:
     int n;
public:
     Calculator(int i=0){n=i;}
        Calculator operator+(Calculator c);
     Calculator operator++();
     Calculator operator++(int);
     friend Calculator operator--(Calculator &c);
     friend Calculator operator--(Calculator &c,int);
     void display();
};
Calculator Calculator::operator +(){
Calculator temp;
temp.n=n+c.n;
return temp;
}
Calculator Calculator::operator ++(){
++n;
return *this;
}
Calculator Calculator::operator ++(int){
n++;return *this;
}
Calculator operator--(Calculator &c){
--c.n;
return c;
}
Calculator operator--(Calculator &c,int){
c.n--;
return c;
}
void Calculator::display(){
cout<<"counter number ="<<n<<endl;
}
void main()
{
     Calculator c1(1),c2(2),c3;
     c3=c1+c2;
     c1.display();
     c2.display();
     c3.display();
     Calculator a;
     ++a;
     a.display();
     a++;
     a.display();
     --a;
     a.display();
     a--;
     a.display();
}


谢啦。。。已经搞定了！