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9.9 链表及其运用

2024-07-22 14:17:27   220人阅读

单向链表的实现方法：
  1. #include <stdio.h>
  2. #include <stdlib.h>
  4. struct list
  5. {
  6.         int data;
  7.         struct list *next;
  8. };
  10. /*创建一个节点*/
  11. struct list *create_list()
  12. {
  13.         return calloc(sizeof(struct list) , 1);
  14. }
  16. /*打印链表的内容*/
  17. void traverse(struct list *p)
  18. {
  19.         //循环实现
  20.         //p = p->next;//头节点不需要打印
  21.         //while(p)
  22.         //{
  23.         //      printf("%d\n" , p->data);
  24.         //      p = p->next;
  25.         //}
  27.         //递归实现
  28.         if (p->next == NULL)
  29.                 return;
  30.         printf("%d\n" , p->next->data);
  31.         traverse(p->next);
  32. }
  34. /*向链表插入一个节点*/
  35. int insert_list(struct list *p , int n , int data)
  36. {
  37.         while (p && n--)
  38.                 p = p->next;
  39.         if (p == NULL)
  40.                 return 0;
  42.         struct list *node = create_list();
  43.         node->data = data;
  44.         node->next = p->next;
  45.         p->next = node;
  46.         return 1;
  47. }
  49. /*删除链表的一个节点*/
  50. int delete_list(struct list *p , int n)
  51. {
  52.         while (p && n--)
  53.                 p = p->next;
  55.         if (p == NULL)
  56.                 return 0;
  58.         struct list *temp = p->next;
  59.         if (temp == NULL)
  60.                 return 0;
  61.         p->next = temp->next;
  62.         free(temp);
  63.         return 1;
  64. }
  66. /*计算链表节点的数量*/
  67. int count_list(struct list *p)
  68. {
  69.         int count = 0;
  70.         while(p->next)//不计算头节点
  71.         {
  72.                 p = p->next;
  73.                 count++;
  74.         }
  75.         return count;
  76. }
  78. /*清空一个链表,只保留头节点*/
  79. void clear_list(struct list *p)
  80. {
  81.         struct list *head = p;
  82.         p = p->next;
  83.         while(p)
  84.         {
  85.                 struct list * tmp = p->next;
  86.                 free(p);
  87.                 p = tmp;
  88.         }
  89.         head->next = NULL;
  90. }
  92. /*判断一个链表是否为空*/
  93. int empty_list(struct list *p)
  94. {
  95.         if(p->next != NULL)
  96.                 return 0;
  97.         else
  98.                 return 1;
  99. }
  101. /*返回链表指定位置的节点*/
  102. struct list *locale_list(struct list *p , int n)
  103. {
  104.         p = p->next;
  105.         while(p && n--)
  106.         {
  107.                 p = p->next;
  108.         }
  109.         return p;
  110. }
  112. /*返回数据等于data的节点*/
  113. struct list *data_list(struct list *p , int data)
  114. {
  115.         p = p->next;
  116.         while(p)
  117.         {
  118.                 if(p->data == data)
  119.                         return p;
  120.         }
  121.         return NULL;
  122. }
  124. /*返回数据等于data的节点位置*/
  125. int data_pos(struct list *p , int data)
  126. {
  127.         int index = 0;
  128.         p = p->next;
  129.         while(p)
  130.         {
  131.                 if(p->data == data)
  132.                         break;
  133.                 p = p->next;
  134.                 index++;
  135.         }
  136.         return index;
  137. }
  139. /*返回链表中最后一个节点*/
  140. struct list *last_list(struct list *p)
  141. {
  142.         while(p->next)
  143.         {
  144.                 p = p->next;
  145.         }
  146.         return p;
  147. }
  149. /*合并两个链表，结果放入第一个链表内*/
  150. void merge_list(struct list *p , struct list *q)
  151. {
  152.         struct list *p_last = last_list(p);
  153.         p_last->next = q->next;
  154.         free(q);
  155. }
  157. /*逆置一个链表*/
  158. struct list *reverse_list(struct list *p)
  159. {
  160.         struct list *pre = p;
  161.         struct list *cur = p->next;
  162.         struct list *next = NULL;
  163.         struct list *last = p->next;
  165.         while(cur)
  166.         {
  167.                 next = cur->next;
  168.                 cur->next = pre;
  169.                 pre = cur;
  170.                 cur = next;
  171.         }
  173.         last->next = NULL;
  174.         p->next = pre;
  175. }
  178. int main(void)
  179. {
  180.         struct list *head = create_list();
  181.         int i;
  182.         for (i = 0 ; i < 4 ; i++)
  183.         {
  184.                 insert_list(head,i,i);
  185.         }
  186.         traverse(head);
  187.         printf("%d\n",last_list(head)->data);
  188.         return 0;
  189. }

head  -> first -> second -> null

优化后的链表程序：
  1. #include <stdio.h>
  2. #include <stdlib.h>
  4. struct list
  5. {
  6.         int data;
  7.         struct list * next;
  8. };
  10. //打印一个链表
  11. void traverse_list(struct list *ls)
  12. {
  13.         struct list * p = ls->next;//不打印头节点
  14.         while(p)
  15.         {
  16.                 printf("%d\n",p->data);
  17.                 p = p->next;
  18.         }
  19. }
  21. //创建一个节点空间
  22. struct list *create_list()
  23. {
  24.         return calloc(sizeof(struct list) , 1);
  25. }
  27. //插入一个节点
  28. struct list *insert_list(struct list * ls , int n , int data)
  29. {
  30.         struct list * p = ls;
  31.         while(p && n--)
  32.         {
  33.                 p = p->next;
  34.         }
  35.         if(!p)
  36.                 return NULL;
  37.         struct list *node = create_list();
  38.         node->next = p->next;
  39.         node->data = data;
  40.         p->next = node;
  41.         return p;
  42. }
  44. //删除一个节点
  45. int delete_list(struct list *ls , int n)
  46. {
  47.         struct list *p = ls;
  48.         while (p && n--)
  49.         {
  50.                 p = p->next;
  51.         }
  52.         struct list *tmp = p->next;
  53.         p->next = tmp->next;
  54.         free(tmp);
  55. }
  57. //初始化一个链表
  58. struct list *init_list(int n)
  59. {
  60.         struct list *head = create_list();
  61.         int i;
  62.         for(i = 0 ; i < n ; i++)
  63.                 insert_list(head,i,i);
  64.         return head;
  65. }
  67. //统计节点的数量
  68. int count_list(struct list *ls)
  69. {
  70.         struct list * p = ls->next;
  71.         int count = 0;
  72.         while(p)
  73.         {
  74.                 p = p->next;
  75.                 count++;
  76.         }
  77.         return count;
  78. }
  80. //清空链表
  81. void clear_list(struct list *ls)
  82. {
  83.         struct list * p = ls->next;
  84.         while(p)
  85.         {
  86.                 struct list * tmp = p->next;
  87.                 free(p);
  88.                 p = tmp;
  89.         }
  90.         ls->next = NULL;
  91. }
  93. //判断一个链接是否为空
  94. int empty_list(struct list *ls)
  95. {
  96.         struct list *p = ls->next;
  97.         if (p!=NULL)
  98.                 return 0;
  99.         else
  100.                 return 1;
  101. }
  103. //返回链表指定位置的节点
  104. struct list *locale_list(struct list *ls , int n)
  105. {
  106.         struct list * p = ls->next;
  107.         while(p && n--)
  108.         {
  109.                 p = p->next;
  110.         }
  111.         return p;
  112. }
  114. //返回链接等于data的节点
  115. struct list *data_list(struct list *ls , int data)
  116. {
  117.         struct list *p = ls->next;
  118.         while (p)
  119.         {
  120.                 if (p->data == data)
  121.                         break;
  122.                 p = p->next;
  123.         }
  124.         return p;
  125. }
  127. //返回链表等于data的位置
  128. int pos_list(struct list *ls , int data)
  129. {
  130.         struct list *p = ls->next;
  131.         int index = 0;
  132.         while (p)
  133.         {
  134.                 if(p->data == data)
  135.                         break;
  136.                 p = p->next;
  137.                 index++;
  138.         }
  139.         return index;
  140. }
  143. //得到最后一个节点
  144. struct list *last_list(struct list *ls)
  145. {
  146.         struct list *p = ls->next;
  147.         struct list *pre = p;
  148.         while(p)
  149.         {
  150.                 pre = p;
  151.                 p = p->next;
  152.         }
  153.         return pre;
  154. }
  156. //合并两个链表，放入第一个链表中
  157. void merge_list(struct list *ls1 , struct list *ls2)
  158. {
  159.         struct list *last = last_list(ls1);
  160.         last->next = ls2->next;
  161.         free(ls2);
  162. }
  164. //链表逆置
  165. void reverse_list(struct list *ls)
  166. {
  167.         struct list *pre = ls;
  168.         struct list *cur = ls->next;
  169.         struct list *next = NULL;
  170.         struct list *last = ls->next;
  172.         while (cur)
  173.         {
  174.                 next = cur->next;
  175.                 cur->next = pre;
  176.                 pre = cur;
  177.                 cur = next;
  178.         }
  179.         last->next = NULL;
  180.         ls->next = pre;
  181. }
  185. int main(void)
  186. {
  187.         struct list *head = init_list(10);
  188.         traverse_list(head);
  189.         return 0;
  190. }

注重理解下面左值和右值的区别
  1. node->next = p->next;
  2. p->next = node;


把本班的同学读入到结构体数组里，加上序号，利用链表并且冒泡排序。
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4. #include <time.h>
  5. struct student
  6. {
  7.         int ID;
  8.         char name[20];
  9. };
  11. struct list
  12. {
  13.         struct student st;
  14.         struct list *next;
  15. };
  17. struct list *create_list()
  18. {
  19.         return calloc(1,sizeof(struct list));
  20. }
  22. struct list *insert_list(struct list *ls , int n, struct student s)
  23. {
  24.         struct list *p = ls;
  25.         while (p && n--)
  26.                 p = p->next;
  27.         if(!p)
  28.                 return NULL;
  29.         struct list *node = create_list();
  30.         node->st = s;
  31.         node->next = p->next;
  32.         p->next = node;
  33.         return node;
  34. }
  35. void traverse_list(struct list *ls)
  36. {
  37.         struct list *p = ls->next;
  38.         while(p)
  39.         {
  40.                 printf("%d:%s\n",p->st.ID,p->st.name);
  41.                 p = p->next;
  42.         }
  43. }
  45. void init_list(struct list *ls)
  46. {
  47.         struct list *head = ls;
  48.         FILE *fp = fopen("student.bin","r");
  49.         while(!fp)
  50.                 return;
  52.         struct student st;
  53.         int index = 0;
  54.         while(fread(&st,sizeof(struct student),1,fp) > 0)
  55.         {
  56.                 insert_list(head,index,st);
  57.                 index++;
  58.         }
  60. }
  62. void sort_list(struct list *ls , int n)
  63. {
  64.         struct list *p = NULL;
  65.         struct student tmp;
  66.         int i,j,min;
  67.         for (i = 0; i < n ; i++)
  68.         {
  69.                 p = ls->next;
  70.                 for (j = 0; j < n-i-1; j++)
  71.                 {
  72.                         if (p->st.ID > p->next->st.ID)
  73.                         {
  74.                                 tmp = p->st;
  75.                                 p->st = p->next->st;
  76.                                 p->next->st = tmp;
  77.                         }
  78.                         p = p->next;
  79.                 }
  80.         }
  81. }
  83. void init_stubin()
  84. {
  85.         srand((unsigned)time(NULL));
  86.         FILE *fp1 = fopen("student.txt","r");
  87.         FILE *fp2 = fopen("student.bin","w");
  88.         while(!fp1 || !fp2)
  89.                 return;
  91.         char buf[1024];
  92.         struct student st;
  93.         memset(&st,0,sizeof(st));
  95.         int arr[42] = {0};
  96.         int pos;
  97.         while(fgets(buf,sizeof(buf),fp1) != NULL)
  98.         {
  99.                 if(buf[strlen(buf)-1] == ‘\n‘)
  100.                         buf[strlen(buf)-1] = ‘\0‘;
  101.                 pos = rand()%42;
  102.                 while(arr[pos] == 1)
  103.                         pos = rand()%42;
  104.                 arr[pos] = 1;
  105.                 st.ID = pos;
  106.                 strcpy(st.name,buf);
  107.                 fwrite(&st,sizeof(st),1,fp2);
  108.         }
  109.         fclose(fp1);
  110.         fclose(fp2);
  111. }
  113. int main(void)
  114. {
  115.         init_stubin();
  116.         struct list *head = create_list();
  117.         init_list(head);
  118.         //traverse_list(head);
  119.         sort_list(head,42);
  120.         traverse_list(head);
  121.         return 0;
  122. }



来自为知笔记(Wiz)


9.9 链表及其运用


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