友員関数(17)

#ifndef _A_H_
#define _A_H_
#include
using namespace std;

class A {
private:
	int a;
public:
	void show();
	friend void display();//      
};
#endif

#include "A.h"
void A::show() {
	cout << "A::show()" << endl;
}

void display() {
	//            
	A A1;
	A1.a = 1;
	cout << "friend  display() a = " <<  A1.a << endl;
}

#include "A.h"

int main() {
	A  a1;
	//a1.a = 1;                
	a1.show();

	//a1.display();               
	display();
	return 0;
}