c++友元类找错啊，大虾们看看哪里错了

#include <iostream>
using namespace std;
class Engine
{
friend class Fuel;
public:
void GetA (int A){a=A;}
private:
int a;
};

class Fuel
{
public:
int ShowA()
{
return a;
}
void main()
{
Engine CAR;
Fuel car;
CAR.GetA(30);
car.ShowA();
}

总出现fatal error C1004: unexpected end of file found怎么改啊

加上#include "stdafx.h"