C语言单链表增删改查基本操作

C语言单链表增删改查基本操作

  1 #include 
  2 #include 
  3 #define LEN sizeof(NODE)
  4 
  5 typedef struct _NODE//节点声明
  6 {
  7     int val;
  8     struct _NODE* next;
  9 } NODE, *PNODE;
 10 
 11 void print(PNODE head){//打印所有节点
 12     while (head)
 13     {
 14         printf("%3d",head->val);
 15         head = head->next;
 16     }
 17     printf("\n");
 18 }
 19 
 20 void insertHead(PNODE *pHead, int val){//头插法
 21     PNODE n = (PNODE)malloc(LEN);
 22     n->val = val;
 23     n->next = *pHead;
 24     *pHead = n;
 25 }
 26 
 27 void insertTail(PNODE *pHead, int val){//尾插法
 28     PNODE t = *pHead;
 29     PNODE n = (PNODE)malloc(LEN);
 30     n->val = val;
 31     n->next = NULL;
 32     if (*pHead == NULL)
 33     {
 34         n->next = *pHead;
 35         *pHead = n;
 36     }else{
 37         while (t->next)
 38         {
 39             t = t->next;
 40         }
 41         t->next = n;
 42     }
 43 }
 44 
 45 void deleteHead(PNODE *pHead){//删除头
 46     if (*pHead == NULL)
 47     {
 48         return;
 49     }
 50     else
 51     {
 52         PNODE t = *pHead;
 53         *pHead = (*pHead)->next;
 54         free(t);
 55     }
 56 }
 57 
 58 void deleteTail(PNODE *pHead){//删除尾
 59     PNODE t = *pHead;
 60     if (t == NULL)
 61     {
 62         return;
 63     }
 64     else if (t->next == NULL)
 65     {
 66         free(t);
 67         *pHead = NULL;
 68     }
 69     else{        
 70         while (t->next->next != NULL)
 71         {
 72             t = t->next;
 73         }
 74         free(t->next);
 75         t->next = NULL;
 76     }
 77 }
 78 
 79 PNODE findByVal(PNODE head, int val){//根据值找到满足条件的第一个节点
 80     while (head != NULL && head->val != val)
 81     {
 82         head = head->next;
 83     }
 84     return head;
 85 }
 86 
 87 PNODE findByIndex(PNODE head, int index){//根据索引找节点
 88     if (index == 1)
 89     {
 90         return head;
 91     }
 92     else
 93     {
 94         int c = 1;
 95         while (head != NULL && index != c)
 96         {
 97             head = head->next;
 98             c++;
 99         }
100     }
101     return head;
102 }
103 
104 void insertByIndex(PNODE *pHead, int index, int val){//根据索引插入节点
105     if (index == 1)
106     {
107         insertHead(pHead, val);
108     }
109     else
110     {
111         PNODE t = findByIndex(*pHead,index - 1);
112         if (t == NULL)
113         {
114             return;
115         }
116         else
117         {
118             PNODE n = t->next;
119             t->next = (PNODE)malloc(LEN);
120             t->next->next = n;
121             t->next->val = val;
122         }
123     }
124 }
125 
126 void deleteByIndex(PNODE *pHead, int index)//根据结点索引删除结点
127 {
128     if (index == 1)
129     {
130         deleteHead(pHead);
131     }
132     else
133     {
134         PNODE t= findByIndex(*pHead, index - 1);
135         if (t == NULL || t->next == NULL)
136         {
137             return;
138         }else{
139             PNODE n = t->next->next;
140             free(t->next);
141             t->next = n;
142         }
143     }
144 }
145 
146 void deleteByVal(PNODE *pHead, int val)//根据值删掉第一个满足条件的
147 {
148     if (*pHead == NULL)//如果空表退出
149     {
150         return;
151     }
152     else
153     {
154         if ((*pHead)->val == val)//如果第一个就是，删头
155         {
156             deleteHead(pHead);
157         }
158         else
159         {
160             PNODE t = *pHead;
161             while (t->next != NULL && t->next->val != val)//遍历，若t的next为空或者next是要找的节点则退出
162             {
163                 t = t->next;
164             }
165             if (t->next)//如果t指向要找的结点的上一个节点
166             {
167                 PNODE n = t->next->next;//删除要找的结点
168                 free(t->next);
169                 t->next = n;
170             }
171         }
172     }
173 }
174 
175 void clear(PNODE *pHead)//清除链表
176 {
177     while ((*pHead) != NULL)
178     {
179         deleteHead(pHead);//从头删除
180     }
181 }
182 
183 void main()
184 {
185     PNODE head = NULL;
186 
187     insertTail(&head,1);
188     deleteHead(&head);
189     insertTail(&head,2);
190     insertTail(&head,3);
191     insertTail(&head,4);
192     insertTail(&head,5);
193     insertTail(&head,6);
194 
195     print(head);
196     insertByIndex(&head, 6, 9);
197     print(head);
198     //deleteByIndex(&head,3);
199     deleteByVal(&head, 2);
200     print(head);
201     clear(&head);
202     print(head);
203     insertByIndex(&head,1,12);
204     print(head);
205 }

 

转载于:https://www.cnblogs.com/hzy3774/archive/2012/08/07/2627508.html