刪除鏈接列表中的節點

Question

嗨我試圖刪除鏈接列表中的節點。我首先試驗如何刪除頭部和尾部節點。頭部刪除似乎可行，但刪除後的尾部不會。當我運行代碼時，尾部曾經的位置被垃圾值替換。任何人都可以找出原因嗎？非常感謝！未來要刪除

Answer 1

考慮node_1點node_2（只是一個2節點的情況下） 只要看看這段代碼

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

node_1點node_2。它仍然指向那裏。一旦你刪除了node_2，node_1仍然會指向node_2（或者一旦node_2被刪除，就會造成垃圾）&，所以你必須確保node_1指向NULL。即最後一個應該指向null。

像

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

Answer 2

保持一個節點你的尾巴和頭指針是一樣的嗎？你不檢查它。因此你可能會刪除你認爲是Head的指針，這也是一個尾巴。另外，如果它的下一個頭部或尾部是什麼？

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

如果什麼節點

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

這種說法

while (pMyPointer != NULL) 

你的指針可能指向NULL時退出循環，因此它會跳過尾指針。

而是嘗試

while (pMyPointer->m_pNext != NULL) 

您還需要進行第二次最後一個節點指向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;