c++自定义指针类型、*和->运算符重载

#include<iostream>
#include<memory>
using namespace std;

class A
{
public:
A(int id)
{
this->id = id;
cout<<"A(int)"<<endl;
}
~A()
{
cout<<"~A()"<<endl;
}
void print()
{
cout<<this->id<<endl;
}

private:
int id;
};

class Ptr
{
public:
//传入一个对象的指针
Ptr(A *ptr)
{
this->ptr = ptr;
}
//匿名对象周期完毕自动释放
~Ptr()
{
if(this->ptr!=NULL)
{
delete this-> ptr;
this->ptr = NULL;
cout<<"auto delete"<<endl;
}
}
//返回的是一个对象指针
A* operator->()
{
return this->ptr;
}1
//*p返回的就是对象
A& operator*()
{
//类中的ptr已经被初始化为A
return *(this->ptr);
}

private:
A *ptr;
};

void test_auto_ptr()
{
//special grammer
//匿名对象完成功能后，会自动调用类A的析构函数
auto_ptr<A> ptr(new A(11));
ptr->print();
}

void test()
{
//A *a = new A(10);//这种简单的不delete会形成内存泄露
Ptr ptr(new A(12));
ptr->print();
(*ptr).print();
}

int main(void)
{
test();
cout<<"===="<<endl;
test_auto_ptr();

return 0;
}