友元函數的代碼

#include <stdlib.h>

#include <iostream>

using namespace std;
#include "stdafx.h"

class MyClass;

class A
{


public:

	A()
	{
		m_ia = 0;
		printf("A()\n");
	}
	A& operator=(const A &a)
	{
		printf("=\n");

		return *this;
	}

	friend void display1(MyClass);
	friend class MyClass;
	
private:
	int m_ia;
};

class MyClass
{

	void output();
private:

};

void MyClass::output()
{
	A a;
	a.m_ia = 10;
}
class B
{
friend void display1(MyClass);

};
void display1(MyClass a)
{
	//printf("\n%d\n",a.m_ia);
	cout <<"ddd" << endl;
}

int main(void)
{
	//A a;
	MyClass  b;
	//a = b;
	
	display1(b);
	display1(b);
	getchar();


	return 0;
}