如何删除有指针成员的类的指针？ [英] How delete a pointer of classes which has pointer members?

问题描述

我的意思是，如果我有一些类像：

I mean, if i have some class like:

class A{
    int* pi;
};
*A pa;

code> pi 被删除？

when i call delete pa, will pi be deleted?

推荐答案

您需要定义一个析构函数 delete pi; 。此外，您还需要定义一个复制构造函数和赋值运算符，否则当复制 A 的实例时，两个对象将指向同一个 int ，当 A 的一个实例被销毁而留下另一个 A 带有悬空指针。

You need to define a destructor to delete pi;. In addition you also need to define a copy constructor and assignment operator otherwise when an instance of A is copied two objects will be pointing to the same int, which will be deleted when one of the instances of A is destructed leaving the other instance of A with a dangling pointer.

例如：

class A
{
public:
    // Constructor.
    A(int a_value) : pi(new int(a_value)) {}

    // Destructor.
    ~A() { delete pi; }

    // Copy constructor.
    A(const A& a_in): pi(new int(*a_in.pi)) {}

    // Assignment operator.
    A& operator=(const A& a_in)
    {
        if (this != &a_in)
        {
            *pi = *a_in.pi;
        }
        return *this;
    }
private:
    int* pi;
};

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