#include <iostream>
using namespace std;


struct ListNode {
  int value;
  ListNode* next;
};

void addToDetail(ListNode** pHead, int value) {
  ListNode* pNew = new ListNode();
  pNew->value = value;
  pNew->next = NULL;

  if (*pHead == NULL) {
    *pHead = pNew;
  } else {
    ListNode*
 
 pNode = *pHead;
    while (pNode->next != NULL) {
      pNode = pNode->next;
    }
    pNode->next = pNew;
  }
}

void removeNode(ListNode** pHead, int value) {
    if(pHead == NULL || *pHead == NULL) {
        return;
    }
  ListNode* pToDeleted = NULL;
  if ((*pHead)->value == value) {
    pToDeleted =
 
 *pHead;
    *pHead = (*pHead)->next;
  } else {
    ListNode* pNode = *pHead;
    while(pNode->next != NULL && pNode->next->value != value)
      pNode = pNode->next;

    if (pNode->next != NULL && pNode->next->value == value) {
      pToDeleted = pNode->
 
next;
      pNode->next = pNode->next->next;
    }
  }

  if (pToDeleted != NULL) {
    delete pToDeleted;
    pToDeleted = NULL;
  }

}

void visitList(ListNode** pHead) {
  if (pHead == NULL || *pHead == NULL) {
    return;
  }

  ListNode* tmp = *pHead;
  while(tmp != NULL) {
    cout << tmp->value << endl;
    tmp = tmp->next;
  }
}

int main(int argc, char const *argv[]) {
  ListNode** pHead = NULL;
  // *pHead = head;
  ListNode* head = NULL;
  pHead = &head;

  addToDetail(pHead, 1);
  addToDetail(pHead, 2);
  addToDetail(pHead, 3);
  addToDetail(pHead, 4);
  visitList(pHead);
  removeNode(pHead, 4);
  removeNode(pHead, 1);
  removeNode(pHead,2);
  visitList(pHead);
  return 0;
}

需要注意的地方：

• 當頭節點是NULL的時候，插入的第一個節點就是頭節點，因此使用指標的指標指向頭節點指標。