singly linked list 单向链表反转

3763阅读　0评论2012-01-13　jonas_mao
分类：C/C++

以前一直都没写过，今天写了个：
 
  1. /*
  2.  * reserve the linked list without circular 链表反向
  3.  */

  5.  #include <stdio.h>
  6.  #include <stdlib.h>

  8.  struct linklist
  9.  {
  10.    struct linklist *next;
  11.    
  12.    int key;
  13.  };

  15.  void
  16.  printf_linklist (struct linklist *head)
  17.  {
  18.    struct linklist *lnode;
  19.    
  20.    if (head == NULL)
  21.      printf ("%% linklist is NULL\n");
  22.     
  23.    lnode = head;
  24.    printf (" Linklist : ");
  25.    for (; lnode; lnode = lnode->next)
  26.      {
  27.      printf (" %d ", lnode->key);
  28.      }
  29.    
  30.    return;
  31.  }

  33.  struct linklist *
  34.  reverse_linklist (struct linklist *head)
  35.  {
  36.    struct linklist *re_link;
  37.    struct linklist *link_tmp;
  38.    struct linklist *link_next;
  39.    
  40.    if (head == NULL)
  41.      return NULL;

  43.    re_link = head;
  44.    link_next = head->next;
  45.    re_link->next = NULL;
  46.    
  47.    while (link_next)
  48.      {
  49.      link_tmp = link_next;
  50.        
  51.        link_next = link_next->next;
  52.        
  53.        link_tmp->next = re_link;
  54.        re_link = link_tmp;    
  55.      }
  56.     
  57.     return re_link;
  58.  }

  60.  struct linklist *
  61.  create_linklist (int numb)
  62.  {
  63.    int i;
  64.    struct linklist *lists[numb];
  65.    struct linklist *lnode;
  66.    struct linklist *lnode_n;

  68.    for (i = 0; i < numb; i++)
  69.      {
  70.      lists[i] = (struct linklist *) malloc (sizeof (struct linklist));
  71.         if (lists[i] == NULL)
  72.          break;
  73.         
  74.         lists[i]->key = i;
  75.         lists[i]->next = NULL;
  76.         if (i > 0)
  77.          lists[i-1]->next = lists[i];
  78.      }
  79.     
  80.    if (i < numb)
  81.      {
  82.      for (lnode = lists[0]; lnode; lnode = lnode_n)
  83.      {
  84.          lnode_n = lnode->next;
  85.          free (lnode);
  86.          lnode = NULL;
  87.          }
  88.         
  89.      return NULL;
  90.      }
  91.    
  92.    return lists[0];
  93.  }

  95.  void
  96.  destroy_linklist (struct linklist *head)
  97.  {
  98.    struct linklist *lnode;
  99.    struct linklist *lnode_n;
  100.    
  101.    if (head == NULL)
  102.      return;
  103.    
  104.    for (lnode = head; lnode; lnode = lnode_n)
  105.      {
  106.      lnode_n = lnode->next;
  107.      free (lnode);
  108.      lnode = NULL;
  109.      }
  110.   
  111.    return;
  112.  }
  113.  int
  114.  main (void)
  115.  {
  116.    int numb;
  117.    struct linklist *head;
  118.    
  119.    printf ("\n pls enter the listnode numb : ");
  120.    scanf ("%d", &numb);
  121.    
  122.    head = create_linklist (numb);
  123.    printf ("\n before reverse :");
  124.    printf_linklist (head);
  125.    
  126.    head = reverse_linklist (head);
  127.    printf ("\n after reverse :");
  128.    printf_linklist (head);
  129.    
  130.    destroy_linklist (head);
  131.    
  132.    return 0;
  133.  }

运行结果：(gcc, 今天利用这个特意试了下gdb 调试)

 

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