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", 20);
    Pointer<Persion> p1 = NULL;
    p1 = p;
    p1->show();
    return 0;
}