c++ 中的this指针是如何工作的？

 通过一个例子，看看不使用本身的this，而是自己实现THIS，了解this指针的工作机制：

#include <stdio.h>
#include <iostream>
#include <string>
using namespace std;

//

// 

//
struct  X
{
private:
	int len;
	char *ptr;
public:
	int GetLen(X* const THIS)
	{
		return THIS->len; //
	}

	char *GetPtr(X* const THIS)
	{
		return THIS->ptr;
	}

	X& Set(X* const, char *);
	X& Cat(X* const, char *);;
	X& Copy(X* const, X&);
	void Print(X* const);
};

X& X::Set(X* const THIS,char *pc)
{
	THIS->len = strlen(pc);
	THIS->ptr = new char[THIS->len];
	strcpy(THIS->ptr, pc);

	return *THIS;
}

X& X::Cat(X* const THIS,char *pc)
{
	THIS->len += strlen(pc);
	strcat(THIS->ptr, pc);
	return *THIS;
}


X& X::Copy(X* const THIS, X& x)
{
	THIS->Set(THIS, x.GetPtr(&x));
	return *THIS;
}

void X::Print(X* const THIS)
{
	cout<<THIS->ptr<<endl;
}

void main()
{
	X x;

	x.Set(&x, "hello");
	x.Cat(&x, "Yes\n\n");

	x.Print(&x);

	X y;
	y.Copy(&y, x);
	y.Print(&y);

}