复习下单链表的逆置，留作后看：

 

先上张图，便于理解代码：

代码贴上：

  1 /************************************************************************/
  2 /* create by leisc    2014.07.11                                           */
  3 /************************************************************************/
  4 
  5 #include <iostream>
  6 using namespace std;
  7 
  8 typedef struct _listnode
  9 {
 10     int data;
 11     _listnode *pNext;
 12 }LISTNODE;
 13 
 14 //打印链表
 15 int printlist(const LISTNODE *head)
 16 {
 17     int ret = 0;
 18     if (head == NULL)
 19     {
 20         ret = -1;
 21         return ret;
 22     }
 23     cout << endl;
 24     for (LISTNODE *tmp = (LISTNODE*)head->pNext; tmp != NULL; tmp = tmp->pNext)
 25     {
 26         printf("%d ", tmp->data);
 27     }
 28     cout << endl;
 29     return ret;
 30 }
 31 
 32 int CreateAndIniList(LISTNODE ** list)
 33 {
 34     int n = 1;//记录链表元素数量
 35     int cdata = 0;//链表元素数据存储
 36     int ret = 0;
 37 
 38     LISTNODE *pHead = NULL;
 39     LISTNODE *pTmp = NULL;
 40     LISTNODE *pCur = NULL;
 41     //c写法创建新节点
 42     //pPri = pCur = (LISTNODE *)malloc(sizeof(LISTNODE));
 43     pHead = pCur = new LISTNODE;
 44     if (pCur == NULL || pHead == NULL)
 45     {
 46         ret = -1;
 47         return ret;
 48     }
 49 
 50     //头节点初始化
 51     pHead->data = 0;
 52     pHead->pNext = NULL;
 53     pCur = pHead;
 54 
 55     cout << "Please enter the data you want to insert into the list(enter -1 to end!):" << endl;
 56     cout << "The " << n << "'th node data:";
 57     cin >> cdata;
 58     //循环添加链表元素，采用尾插法
 59     while (cdata != -1)
 60     {
 61         pTmp = new LISTNODE;
 62 
 63         pTmp->data = cdata;
 64 
 65         pTmp->pNext = NULL;
 66 
 67         pCur->pNext = pTmp;
 68         pCur = pTmp;
 69         n++;
 70         cout << "The" << n << "'th node data:";
 71         cin >> cdata;
 72     }
 73 
 74     *list = pHead;
 75     return ret;
 76 }
 77 
 78 int ReverseList(LISTNODE **list)
 79 {
 80     if (list == nullptr)//判断是否是空链表
 81     {
 82         return -1;
 83     }
 84 
 85     //申请新节点，将入参接过来
 86     LISTNODE* reList = new LISTNODE;
 87     reList = *list;
 88 
 89     //判断是否是空链表或者只有一个元素
 90     if (reList->pNext == nullptr ||reList->pNext->pNext == nullptr)
 91     {
 92         return -1;
 93     }
 94     
 95     //采用双节点跳马式循环修改指针指向
 96     LISTNODE* pPre = nullptr;    //指向前面一个节点
 97     LISTNODE* pCur = nullptr;    //指向后面一个节点
 98 
 99     pPre = reList->pNext;        //将pPre指向第一个节点
100     pCur = pPre->pNext;            //将pCur指向第二个节点
101     //reList->pNext = nullptr;    //这里可以将头节点指空，当然就那么放着也行
102     pPre->pNext = nullptr;        //首先需要把第一个节点的的指向赋空，要不然就死循环了
103     LISTNODE* pTemp = nullptr;    //申请一个缓存指针，用于存储向后的节点地址
104 
105     //循环进行指针逆置
106     while (pCur)
107     {
108         pTemp = pCur->pNext;//将pCur的下一个地址缓存起来
109         pCur->pNext = pPre; //将pCur的下一个指向他的前一个，即pPre
110         //两个指针同时向后跳一
111         pPre = pCur;
112         pCur = pTemp;
113     }
114 
115     //最后将头节点指向逆置后的第一个节点，即pPre
116     reList->pNext = pPre;
117 
118     return 0;
119 }
120 
121 int main()
122 {
123     LISTNODE *pHead = NULL;
124 
125     CreateAndIniList(&pHead);
126     cout << "原始链表：" << endl;
127     printlist(pHead);
128 
129     ReverseList(&pHead);
130 
131     cout << "逆序后的链表" << endl;
132     printlist(pHead);
133 
134     return 0;
135 }

运行结果：