结构中带有类的链表无法使布尔操作正常工作

发布于 2024-10-20 09:34:50 字数 706 浏览 1 评论 0原文

我似乎无法让 Boolean 操作像我想象的那样工作。

/////.h file

class linkD
{

  private:
struct ListNode{
    driver driver;   ////class 
    ListNode *next;
};
ListNode *head;

///.cpp file

  void linkD::deleteNode(driver d){

ListNode *nodePtr;
ListNode *previousNode;
ListNode *newNode;
newNode=new ListNode;
newNode->next=NULL;
newNode->driver=d;

if(!head)
    return;
if(head->driver==d) //the problem is right here.
{
    nodePtr=head->next;
    delete head;
    head=nodePtr;
}

head->driver==d 给出了一条红线（没有运算符“==”与这些操作数匹配）

我认为这是因为 head->driver< /code> 未初始化，但我可能是错的，我不确定如何初始化它，因为它位于未初始化的结构内。

原文

I can't seem to get Boolean operation working like I thought it works.

/////.h file

class linkD
{

  private:
struct ListNode{
    driver driver;   ////class 
    ListNode *next;
};
ListNode *head;

///.cpp file

  void linkD::deleteNode(driver d){

ListNode *nodePtr;
ListNode *previousNode;
ListNode *newNode;
newNode=new ListNode;
newNode->next=NULL;
newNode->driver=d;

if(!head)
    return;
if(head->driver==d) //the problem is right here.
{
    nodePtr=head->next;
    delete head;
    head=nodePtr;
}

head->driver==d gives a redline (no operator "==" matches these operands)

I think it is because head->driver is uninitialized but I might be wrong and I am not sure how to initialize it since it's inside a uninitialized struct.

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荭秂 2024-10-27 09:34:50

那是因为 driver 是一个类对象。

您必须为类定义相等运算符。

您是否期望类对象像指针一样（如在 Java 中，即它们可以为 NULL）

如果您想测试驱动程序对象的相等性，请像这样定义它：

class driver
{
    public:
        bool operator==(driver const& rhs) const
        {
            return  x == rhs.x && y == rhs.y && z == rhs.z;
        }
    private:
        int x;
        int y;
        int z;
};

int test
{
     driver x;
     driver y;

     if (x == y)   // this calls x.operator==(y)
     {             // So y is the rhs parameter.
     }
}

That's because driver is a class object.

You have to define the equality operator for a class.

Are you expecting class object to be pointer like (as in Java i.e. They can be NULL)

If you want to test driver objects for equality define it like this:

class driver
{
    public:
        bool operator==(driver const& rhs) const
        {
            return  x == rhs.x && y == rhs.y && z == rhs.z;
        }
    private:
        int x;
        int y;
        int z;
};

int test
{
     driver x;
     driver y;

     if (x == y)   // this calls x.operator==(y)
     {             // So y is the rhs parameter.
     }
}

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