13.7 手柄(Handle)

//13.7.1 对像指针问题(Object Pointer Problem)
//13.7.2 对像指针的外套(The Coat of Object Pointer)
//Sony Handle的应用

/*#include "createsony.h"
#include "sonyhandle.h"
#include <iostream>
enum{PUREFLAT, PLASMA, LIQUIDCRYSTAL, NANOMETER};

void fsh(SonyHandle& sh)
{
sh->adjustVolume();
sh->switchChannel();
}

void createSonyObject(CreateSony* sp)
{
SonyHandle sh29(createSonyInch29(sp));
SonyHandle sh34(createSonyInch34(sp));
fsh(sh29);
fsh(sh34);
}

int main()
{
if(CreateSony* sp = createCreateSony(PLASMA)){
createSonyObject(sp);
delete sp;
}
system("pause");
return 0;
}*/


#include "createsony.h"
#include "sonyhandle2.h"
#include <iostream>
enum{PUREFLAT, PLASMA, LIQUIDCRYSTAL, NANOMETER};

void fsh(SonyHandle2& sh)
{
	sh->adjustVolume();
	sh->switchChannel();
}

void createSonyObject(CreateSony* sp)
{
	SonyHandle2 sh29(createSonyInch29(sp));
	SonyHandle2 sh34(createSonyInch34(sp));
	fsh(sh29);
	fsh(sh34);
}

int main()
{
	if(CreateSony* sp = createCreateSony(NANOMETER)){
	    createSonyObject(sp);
		delete sp;
	}
    system("pause");
	return 0;
}

　　

#ifndef HEADER_SONYHANDLE
#define HEADER_SONYHANDLE
#include "sony2.h"

class SonyHandle
{
	Sony* sp;
public:
	Sony* operator->(){ return sp;}
	SonyHandle(Sony* pp) : sp(pp){};
	~SonyHandle(){}
};
#endif;

　　

#ifndef HEADER_SONYHANDLE2
#define HEADER_SONYHANDLE2
#include "sony2.h"

class SonyHandle2
{
	Sony* sp;  //定义一个Sony的指针
	int* count;//定义一个整形变量
public:
	
	SonyHandle2(Sony* pp) : sp(pp),count(new int(1)){}; 
	SonyHandle2(const SonyHandle2& sh):sp(sh.sp),count(sh.count){ (*count)++; }


	Sony* operator->(){ return sp;}
	SonyHandle2& operator+(const SonyHandle2& sh){
	    if(sh.sp == sp) return *this; //本来就指向同一个对像的情况
		(*this).~SonyHandle2();
		sp = sh.sp;
		count = sh.count;
		(*count) ++;
		return *this;
	}
	
	
	//SonyHandle(Sony* pp) : sp(pp){};
	~SonyHandle2(){
	    if(--(*count)==0)
		{
			delete sp;
			delete count;
		}
	}
};
#endif;