智能指针

#include <iostream>
#include <string>
using namespace std;
class Test
{
    int i;
public:
    Test(int _val)
    {
        this->i = _val;
        cout << "Test(int _val)" << endl;
    }
    ~Test()
    {
        cout << "~Test()" << endl;
    }
    int get_value()
    {
        return i;
    }
};
class Pointer
{
    Test* mp;
public:
    Pointer(Test *p = NULL)
    {
        mp = p;
    }
    //执行深拷贝
    Pointer(const Pointer&obj)
    {
        mp = obj.mp;
        //剥夺初始化对象的只读属性
        const_cast<Pointer&>(obj).mp = NULL;
    }
    //重载赋值操作符
    Pointer& operator = (const Pointer& obj)
    {
        if (this!= &obj)
        {
            delete mp;
            mp = obj.mp;
            const_cast<Pointer&>(obj).mp = NULL;
        }
        return *this;
    }
    Test* operator ->()
    {
        return mp;
    }
    Test& operator *()
    {
        return *mp;
    }
    ~Pointer()
    {
        delete mp;
    }
    //如果mp等于NULL，返回true:1
    bool isNULL()
    {
        return (mp==NULL);
    }
};
int main()
{
    cout << "Hello World!\n" <<endl;
    //使用类对象来代替指针，在变量p（对象）生命周期结束时
    //执行析构函数，释放变量mp
    Pointer p = new Test(6);
    cout << p->get_value() << endl;
    Pointer p1 = p;
    cout << p.isNULL() << endl;
    cout << p1->get_value() << endl;
}
运行结果：
Hello World!
Test(int _val)
6
1
6
~Test()