单链表的实现及其基本操作

结点的引入

      链表是一种链式存储结构，链式存储结构的特点是用一组任意的存储单元存储数据元素。为了能正确表示数据元素之间的线性关系，需引入结点概念。一个结点表示链表中的一个数据元素，节点中除了储存数据元素的信息， 还必须存放指向下一个节点的的指针（单、双链表的最后一个节点除外，它们存储的是一个空指针NULL）   

结点的结构如下图所示：

  

代码如下：

1 typedef struct node{
2     int data;
3     struct node* pNext;
4 }Node,  *PNode;
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注：这里假设结点中储存的是整型 (int) 的数据

 单链表由多个结点依次连接而成，我们不难想象出它结构：

我们注意到：在第一个结点的前面多了一个头结点，这是为了处理空表的方便而引入的，它的指针指向链表的第一个结点，而它的data域不存放任何信息。

 

单链表的基本操作

 1.创建链表

 1 PNode createList()
 2 {
 3     int len, value;
 4     
 5     PNode pHead = (PNode)(malloc(sizeof(Node)));
 6     PNode pTail = pHead;
 7     pTail->pNext = NULL;
 8     
 9     printf("请输入你要的节点个数：");
10     scanf("%d", &len);
11     for(int i=1;i<=len;i++){
12         printf("请输入第%d个节点的值：", i);
13         scanf("%d", &value);
14         
15         PNode pNew = (PNode)malloc(sizeof(Node));
16         pNew->data = value;
17         pTail->pNext = pNew;
18         pTail = pNew;
19         pTail->pNext = NULL;    
20     }
21     
22     return pHead;
23 }
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2.遍历链表

void traverse(PNode pHead)
{
    printf("遍历结果为:\n");
    PNode pTra = pHead;
    while(pTra->pNext != NULL)
    {
        printf("%d ", pTra->pNext->data);
        pTra = pTra->pNext;
    }
    printf("\n");
}
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3.判断链表是否为空

1 bool isEmpty(PNode pHead)
2 {
3     if(pHead->pNext==NULL)
4       return true;
5     else
6       return false;
7 }
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 4.链表长度

 1 int length(PNode pHead)
 2 {
 3     int len = 0;
 4     while(pHead->pNext!=NULL){
 5         pHead = pHead->pNext;
 6         len++;
 7     }
 8     return len;
 9     
10 }
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 5.插入结点

 1 bool insert(PNode pHead, int pos, int val)
 2 {
 3     if(pos<1 || pos>length(pHead)){
 4         return false;
 5     }else{
 6         PNode pInsert = pHead;
 7         for(int i=1;i<pos;i++){
 8             pInsert = pInsert->pNext;
 9         }
10         
11         PNode pNew = (PNode)malloc(sizeof(Node));
12         pNew->data = val;
13         pNew->pNext = pInsert->pNext;
14         pInsert->pNext = pNew;
15         
16         return true;
17     }
18     
19 }
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 6.删除结点

 1 bool del(PNode pHead, int pos)
 2 {
 3     if(pos<1 || pos>length(pHead)){
 4         return false;
 5     }else{
 6         PNode pDel = pHead;
 7         for(int i=1;i<pos;i++){
 8             pDel = pDel->pNext;
 9         }
10         
11         if(pos==length(pHead)){
12           free(pDel->pNext);
13           pDel->pNext = NULL;    
14         }else{
15             PNode pNext = pDel->pNext->pNext;
16             free(pDel->pNext);
17             pDel->pNext = pNext;
18         }
19         
20         return true;
21         
22     }
23     
24     
25 }
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 7.查找节点

（1）按元素值查找

1 PNode locate(PNode pHead, int value)
2 {
3     PNode p = pHead->pNext;
4     while(p&&p->data!=value){      //NULL 是 0 
5         p = p->pNext;
6     }
7     return p;
8 }
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（2）按序号查找

1 PNode get(PNode pHead, int k)
2 {
3     PNode p = pHead;
4     for(int i=1;i<=k;i++){
5         p = p->pNext;
6     }
7     return p;
8     
9 }
View Code

 

完整代码

  1 #include<stdio.h>
  2 #include<stdlib.h> 
  3 typedef struct node{
  4     int data;
  5     struct node* pNext;
  6 }Node, *PNode;
  7  
  8 PNode createList();   
  9 void traverse(PNode pHead);
 10 bool isEmpty(PNode pHead);
 11 int length(PNode pHead);
 12 bool insert(PNode pHead, int pos, int val);
 13 bool del(PNode pHead, int pos);
 14 PNode get(PNode pHead, int k); //按序号查找
 15 PNode locate(PNode pHead, int value);//按值查找 
 16 
 17 int main(void)
 18 {
 19    //test
 20    
 21    return 0; 
 22 } 
 23 
 24 PNode createList()
 25 {
 26     int len, value;
 27     
 28     PNode pHead = (PNode)(malloc(sizeof(Node)));
 29     PNode pTail = pHead;
 30     pTail->pNext = NULL;
 31     
 32     printf("请输入你要的节点个数：");
 33     scanf("%d", &len);
 34     for(int i=1;i<=len;i++){
 35         printf("请输入第%d个节点的值：", i);
 36         scanf("%d", &value);
 37         
 38         PNode pNew = (PNode)malloc(sizeof(Node));
 39         pNew->data = value;
 40         pTail->pNext = pNew;
 41         pTail = pNew;
 42         pTail->pNext = NULL;    
 43     }
 44     
 45     return pHead;
 46 }
 47 
 48 
 49 void traverse(PNode pHead)
 50 {
 51     printf("遍历结果为:\n");
 52     PNode pTra = pHead;
 53     while(pTra->pNext != NULL)
 54     {
 55         printf("%d ", pTra->pNext->data);
 56         pTra = pTra->pNext;
 57     }
 58     printf("\n");
 59 }
 60 
 61 bool isEmpty(PNode pHead)
 62 {
 63     if(pHead->pNext==NULL)
 64       return true;
 65     else
 66       return false;
 67 }
 68 
 69 int length(PNode pHead)
 70 {
 71     int len = 0;
 72     while(pHead->pNext!=NULL){
 73         pHead = pHead->pNext;
 74         len++;
 75     }
 76     return len;
 77     
 78 }
 79 
 80 bool insert(PNode pHead, int pos, int val)
 81 {
 82     if(pos<1 || pos>length(pHead)){
 83         return false;
 84     }else{
 85         PNode pInsert = pHead;
 86         for(int i=1;i<pos;i++){
 87             pInsert = pInsert->pNext;
 88         }
 89         
 90         PNode pNew = (PNode)malloc(sizeof(Node));
 91         pNew->data = val;
 92         pNew->pNext = pInsert->pNext;
 93         pInsert->pNext = pNew;
 94         
 95         return true;
 96     }
 97     
 98 }
 99 
100 bool del(PNode pHead, int pos)
101 {
102     if(pos<1 || pos>length(pHead)){
103         return false;
104     }else{
105         PNode pDel = pHead;
106         for(int i=1;i<pos;i++){
107             pDel = pDel->pNext;
108         }
109         
110         if(pos==length(pHead)){
111           free(pDel->pNext);
112           pDel->pNext = NULL;    
113         }else{
114             PNode pNext = pDel->pNext->pNext;
115             free(pDel->pNext);
116             pDel->pNext = pNext;
117         }
118         
119         return true;
120         
121     }
122     
123     
124 }
125 
126 PNode get(PNode pHead, int k)
127 {
128     PNode p = pHead;
129     for(int i=1;i<=k;i++){
130         p = p->pNext;
131     }
132     return p;
133     
134 }
135 PNode locate(PNode pHead, int value)
136 {
137     PNode p = pHead->pNext;
138     while(p&&p->data!=value){      //NULL 是 0 
139         p = p->pNext;
140     }
141     return p;
142 }
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posted @ 2017-02-18 23:00  BrysonChen  阅读(14179)  评论(0)  编辑  收藏  举报