[英]Inserting a node in a double linked list
我正在嘗試將一個節點添加到鏈表的開頭。 這是我的代碼,但是當我對它運行測試時,它不起作用。 關於我可能做錯的任何想法? 在此先感謝您的幫助!
void List<T>::insertFront(T const & insert)
{
ListNode * newNode = new ListNode(insert);
if (head != NULL)
{
head->prev = newNode;
head = head->prev;
head->prev = NULL;
}
else
{
head = newNode;
tail = newNode;
}
}
雙向鏈表是以兩種方式鏈接的,您只是以一種方式附加新節點。
你需要一個:
newnode->next = head;
在你取消舊頭之前的那里。
嘗試這個。
下面的方法只是輸入並制作雙重鏈接列表
node DoublyLinkedList()
{
node *list, *tptr, *nptr;
int n, item;
cout << "Enter numbers of node: ";
cin >> n;
list = NULL;
tptr = NULL;
for (int i = 0; i < n; i++)
{
//Input new node value
cout << "Enter Item " << i + 1 << ": ";
cin >> item;
//Creating new node
nptr = new(node);
nptr->back = NULL;
nptr->data = item;
nptr->next = NULL;
if (list == NULL)
{
list = nptr;
tptr = nptr;
}
else
{
tptr->next = nptr;
nptr->back = tptr;
tptr = nptr;
}
}
cout << endl;
tptr = list;
while (tptr != NULL)
{
cout << tptr->data;
tptr = tptr->next;
if (tptr != NULL)
{
cout << "<=>";
}
}
return *list;
}
使用以下方法插入新節點
void InsertToDoubly()
{
node *list, *tptr, *nptr, *pptr;
int newItem;
list = new(node);
tptr = NULL;
pptr = NULL;
*list = DoublyLinkedList(); // See this method implementation above.
cout << endl;
cout << "Input new node value to insert: ";
cin >> newItem;
nptr = new(node);
nptr->back = NULL;
nptr->data = newItem;
nptr->next = NULL;
tptr = list;
int i = 0;
while (tptr != NULL && tptr->data < newItem)
{
pptr = tptr;
tptr = tptr->next;
i++;
}
if (i == 0)
{
// Inserting at the beggining position.
nptr->next = tptr;
tptr->back = nptr;
list = nptr;
}
else if (tptr == NULL)
{
//Inserting at the last position
pptr->next = nptr;
nptr->back = pptr;
}
else
{
//Inserting into the middle position
pptr->next = nptr;
nptr->back = pptr;
nptr->next = tptr;
tptr->back = nptr;
}
tptr = list;
ShowNode(tptr);
cout << endl;
}
主要方法
int main()
{
InsertToDoubly();
}
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