C++语法小记---智能指针

智能指针

• 用于缓解内存泄露的问题

• 用于替代原生指针

• 军规：只能指向堆空间中的对象或变量

• 方法

• 在智能指针的析构函数中调用delete

• 重载"->"操作符，只能重载成成员函数，且不能有参数

• 禁止智能指针的算术运算

• 一块对空间只能被一个智能指针指向

例子

 #include<iostream>
 #include<string>

 using namespace std;

 class Persion
 {
     string name;
     int age;
 public:
     Persion(string name, int age)
     {
         this->name = name;
         this->age = age;
         cout<<"Persion()"<<endl;
     }

     void show()
     {
         cout<<"name = "<<name<<endl;
         cout<<"age = "<<age<<endl;
     }

     ~Persion()
     {
         cout<<"~Persion()"<<endl;
     }
 };

 template<typename T>
 class Pointer
 {
     T* m_ptr;
 public:
     Pointer(T* ptr)
     {
         m_ptr = ptr;
     }

     Pointer(const Pointer& other)
     {
         m_ptr = other.m_ptr;
         const_cast<Pointer&>(other).m_ptr = NULL;
     }

     Pointer& operator = (const Pointer& other)
     {
         if(this != &other)
         {
             if(m_ptr)
             {
                 delete m_ptr;
             }

             m_ptr = other.m_ptr;
             const_cast<Pointer&>(other).m_ptr = NULL;
         }
         return *this;
     }

     T* operator -> ()
     {
         return m_ptr;
     }

     ~Pointer()
     {
         if(m_ptr)
         {
             delete m_ptr;
         }
         m_ptr = NULL;
     }
 };

 int main()
 {
     Pointer<Persion> p = new Persion("zhangsan", );
     Pointer<Persion> p1 = NULL;
     p1 = p;
     p1->show();
     return ;
 }