C++重载程序改错

#include <iostream>
using namespace std;
class Operclass
{
int x;
public:
Operclass();
Operclass operator+(Operclass);
Operclass operator++();
void display();
};
Operclass::Operclass()
{
x=0;
}
void Operclass::display()
{
cout<<"x="<<x<<endl;
}
Operclass Operclass::operator++()
{
Operclass A;
x++;
A.x=x;
return A;
}
Operclass Operclass::operator +(Operclass A)
{
Operclass B;
B.x=x+A.x;
return B;
}
void main()
{
Operclass X,Y,Z;
Z=X+Y;
}