删除链接列表中的节点

Question

嗨我试图删除链接列表中的节点。我首先试验如何删除头部和尾部节点。头部删除似乎可行，但删除后的尾部不会。当我运行代码时，尾部曾经的位置被垃圾值替换。任何人都可以找出原因吗？非常感谢！未来要删除

Answer 1

考虑node_1点node_2（只是一个2节点的情况下） 只要看看这段代码

else if (pMyPointer == m_pTail) 
     m_pTail = m_pTail->m_pPrev; 

node_1点node_2。它仍然指向那里。一旦你删除了node_2，node_1仍然会指向node_2（或者一旦node_2被删除，就会造成垃圾）&，所以你必须确保node_1指向NULL。即最后一个应该指向null。

像

else if (pMyPointer == m_pTail) 
    m_pTail->m_pPrev->next=NULL; 
    m_pTail = m_pTail->m_pPrev; 

Answer 2

保持一个节点你的尾巴和头指针是一样的吗？你不检查它。因此你可能会删除你认为是Head的指针，这也是一个尾巴。另外，如果它的下一个头部或尾部是什么？

void CList :: Remove() { 

    int data = NULL; 

    std::cout<<"Enter value you wish to remove "; 
    std:: cin>> data; 

    cNode *pMyPointer = m_pHead; 

    while (pMyPointer != NULL) 
    { 
     if (pMyPointer->m_nValue == data) { 
      std::cout << "Element found"; 
      goto del; 
     } 

     else { 
      pMyPointer = pMyPointer->m_pNext; 
     } 
    } 

    del: 

    //taking care of the neighbors 
    if (pMyPointer->m_pPrev) 
     pMyPointer->m_pPrev->m_pNext = pMyPointer->m_pNext; 
    if (pMyPointer->m_pNext) 
     pMyPointer->m_pNext->m_pPrev = pMyPointer->m_pPrev; 
    // removing the head 
    if (pMyPointer == m_pHead) 
     m_pHead= m_pHead->m_pNext; 
    //removing the tail 
    if (pMyPointer == m_pTail) 
     m_pTail = m_pTail->m_pPrev; 

    delete pMyPointer; 
} 

Answer 3

如果什么节点

void CList :: Remove() { 

    int data = NULL; 

    std::cout<<"Enter value you wish to remove "; 
    std:: cin>> data; 

    cNode *pMyPointer = m_pHead; 

    while (pMyPointer != NULL) 
    { 
     if (pMyPointer->m_nValue == data) { 
      std::cout << "Element found"; 
      goto del; 
     } 

     else { 
      pMyPointer = pMyPointer->m_pNext; 
     } 
    } 

    del: 

    //removing the head 
    if (pMyPointer == m_pHead) 
     m_pHead= m_pHead->m_pNext; 
    //removing the tail 
    else if (pMyPointer == m_pTail) 
     m_pTail = m_pTail->m_pPrev; 

    delete pMyPointer; 
} 

Answer 4

这种说法

while (pMyPointer != NULL) 

你的指针可能指向NULL时退出循环，因此它会跳过尾指针。

而是尝试

while (pMyPointer->m_pNext != NULL) 

您还需要进行第二次最后一个节点指向NULL。

else if (pMyPointer == m_pTail) { 
    m_pTail = m_pTail->m_pPrev; 
    m_pTail->m_pNext = NULL; 
} 
delete pMyPointer; 

另外，代替goto del，只是使用break;