一个例子说明线性链表的简单操作

typedef struct node
{
    char info;
    struct node *link;  
}NODE;

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 
  4 tyoedef struct node
  5 {
  6     char info;                         /*store the data of the  element*/
  7     struct node *link;              /*store the address of the next element*/
  8 }NODE;
  9 
 10 /******************************************************************************
 11 **function:    listCreate
 12 **description:create a list
 13 **input:         no
 14 **return:       reurn the head pointer
 15 ******************************************************************************/
 16 NODE *listCreate ()
 17 {
 18     NODE *head, *p1, *p2;
 19     cahr ch;
 20     head = (NODE *)malloc(sizeof(NODE));      /*create the head node*/
 21     head->link = NULL;
 22     p1 = head;
 23     while((ch = getchar()) != ‘\n‘)
 24     {
 25         p2 = (NODE *)malloc(sizeof(NODE));    /*create a new node   */
 26         p2->info = ch;
 27         p2->link = NULL; 
 28 
 29         p1->link = p2;                        /*insert the new node */
 30         p1 = p2;
 31     }  
 32     return (head);
 33 }
 34 
 35 /***************************************************************************
 36 **function:    listTravel
 37 **description:travel the element of the list
 38 **input:         the pointer to the node
 39 **return:       void
 40 **************************************************************************/
 41 void listTravel(NODE *ptr)
 42 {
 43     ptr = ptr->link;
 44     while(ptr != NULL)
 45     {
 46         printf("%c ", ptr->info);
 47         ptr = ptr->link;            /*enable the ptr point to the next node*/
 48     }
 49     printf("\n");
 50 }
 51 
 52 /********************************************************************
 53 **function:    listProcess
 54 **description:process the data of list
 55 **input:         two node point la,lb
 56 **return:       reurn a new pointer of the list
 57 *******************************************************************/
 58 NODE *listProcess(NODE *la, NODE *lb)
 59 {
 60     NODE *ptr, *p1, *p2;
 61     int found = 0;
 62 
 63     ptr = lb->link;
 64     while(ptr != NULL)
 65     {
 66         p1 = la->link;
 67         p2 = la;
 68         while(p1 != NULL && !found)
 69         {
 70         if(p1->info == ptr->info)              /*if the two datas equals*/
 71             {
 72                 found = 1;
 73             }
 74             else                               /*point the next element*/
 75             {    
 76                 p2 = p1;
 77                 p1 = p1->link;
 78             }
 79          }
 80             if(found)                          /*delete the node */
 81             {
 82                 p2->link = p1->link;
 83                 free(p1);
 84                 found = 0;
 85             }
 86             else                               /*insert the node */
 87 
 88             {
 89                 p1 = (NODE *)malloc(sizeof(NODE));
 90                 p1->info = ptr->info;
 91                 p1->link = NULL;
 92                 p2->link = p1;
 93             }     
 94         
 95         ptr = ptr->link;                      /*compare the next element */
 96     }
 97     return (la);
 98 }
 99 
100 /*******************************************************************
101 **function:    main
102 **description:complete the task
103 **input:         void
104 **return:        0
105 *******************************************************************/
106 int main(int argc, char *argv[])
107 {
108     NODE *la, *lb;
109     
110     printf("\nthe element of the list A:\n ");
111     la = listCreate();
112     listTravel(la); 
113 
114     printf("\nthe element of the list B:\n ");
115     lb = listCreate();
116     listTravel(lb); 
117 
118     la = process(la, lb);
119     printf("the list (A-B)U(B-A) is\n");
120     listTravel(la); 
121 
122     return 0;
123 }