链表逆序

实现链表逆序的功能

下面是实现链表逆序的函数：

 1 /*

 2  * 把head指针指向的链表逆序

 3  * author:rio_2607

 4  */

 5 void inverse(struct node *head)

 6 {

 7     struct node *current = head;

 8     struct node *current_next = NULL;

 9 

10     //如果是一个空链表或者只有一个元素,则直接返回

11     if(NULL == head || NULL == current->next)

12         return;

13 

14     current_next = current->next;

15 

16     while(current_next->next != NULL)

17     {

18         struct node *temp = current_next->next;

19         current_next->next = current;//逆序指针

20 

21         current = current_next;//两个指针都往后移一个

22         current_next = temp;

23     }

24 

25     //把最后两个节点逆序

26     current_next->next = current;

27     head->next = NULL;

28 

29     head = current_next;//把头指针指向最后一个指针

30 

31 

32     //打印输出结果

33     struct node *t = head;

34     while(t != NULL)

35     {

36         cout << t->data << "  ";

37         t = t->next;

38     }

39 

40 }

其中，struct node的定义是：

1 struct node {

2     int data;

3     struct node *next;

4 };

下面是测试代码：先输入链表的长度，在依次输入每个链表的数据域的数据，然后分别打印输出逆序前后的数据：

 1 int main()

 2 {

 3     struct node *head = NULL;

 4     struct node *current = NULL;

 5     int number;

 6     cout << "please enter the number :" ;

 7     cin >> number;

 8     for(int i = 1;i <=number;++i)

 9     {

10         struct node *temp = (struct node*)new struct node;

11         cin >> temp->data;

12         temp->next = NULL;

13 

14         if(NULL == head)

15             head = temp;

16         else

17             current->next = temp;

18 

19         current = temp;

20 

21     }

22 

23 

24     //打印数据

25     struct node *t = head;

26     cout << "Before inverse:" << endl;

27     while(t != NULL)

28     {

29         cout << t->data << "  ";

30         t = t->next;

31     }

32 

33     cout << endl;

34 

35     cout << "After inverse:" << endl;

36 

37     inverse(head);//链表逆序

38 

39     return 0;

40 }

运行结果如下所示：