单链表操作大全

原地址：http://blog.csdn.net/dxdxsmy/article/details/7346326

如果说你经常在linux中，或者在kernel下面做事的话，一定会碰到链表的操作。
如果你没有真正了解单链表，还是把基础打好吧。
如下程序综合了链表的常用方面，请你下自己写出每个函数，debug并运行，直到运行正确；然后对照参考程序，
比较程序的差异，有时候，可能你测试不全面，会有这样那样的错误，多思考，这样，你才记忆深刻。

#include <stdio.h>  
#include <stdlib.h>  
  
typedef struct node  
{  
    int nDate;  
    struct node *pstnext;  
}Node;  
//链表输出  
void output(Node *head)  
{  
    Node *p = head->pstnext;  
    while(NULL != p)  
    {  
      printf("%d  ", p->nDate);   
      p = p->pstnext;  
    }  
    printf("\r\n");  
}  
//链表建立  
Node* creat()  
{  
    Node *head = NULL, *p = NULL, *s = NULL;  
    int Date = 0, cycle = 1;  
    head = (Node*)malloc(sizeof(Node));  
    if(NULL == head)  
    {  
      printf("分配内存失败\r\n");  
      return NULL;  
    }  
    head->pstnext = NULL;  
  
    p = head;  
    while(cycle)  
    {  
          printf("请输入数据且当输入数据为0时结束输入\r\n");  
          scanf("%d", &Date);  
          if(0 != Date)  
          {  
               s = (Node*)malloc(sizeof(Node));  
               if(NULL == s)  
               {  
                    printf("分配内存失败\r\n");  
                    return NULL;  
               }  
               s->nDate = Date;  
               p->pstnext = s;  
               p = s;  
          }  
          else  
          {  
               cycle = 0;  
          }  
    }  
    p->pstnext = NULL;  
    return(head);  
}  
//单链表测长  
void length(Node *head)  
{  
    Node *p = head->pstnext;  
    int j=0;  
    while(NULL != p)  
    {  
          p = p->pstnext;  
          j++;  
    }  
    printf("%d\r\n", j);  
}  
//链表按值查找  
void research_Date(Node *head, int date)  
{  
    Node *p;  
    int n=1;  
    p = head->pstnext;  
    while(NULL != p && date != p->nDate)  
    {      
          p = p->pstnext;  
          ++n;  
    }  
    if(NULL == p)  
    {  
          printf("链表中没有找到该值");  
    }
    else if(date == p->nDate)  
    {  
          printf("要查找的值%d在链表中第%d个位置\r\n", date, n);  
    }  
    return;  
}  
//按序号查找  
void research_Number(Node *head, int Num)  
{  
    Node *p=head;  
    int i = 0;  
    while(NULL != p && i < Num)  
    {  
          p = p->pstnext;  
          i++;  
    }  
    if(p == NULL)  
    {  
          printf("查找位置不合法\r\n");  
    }
    else if(i == 0)  
    {  
          printf("查找位置为头结点\r\n");  
    }
    else if(i == Num)  
    {  
          printf("第%d个位置数据为%d\r\n", i, p->nDate);  
    }  
}  
//在指定元素之前插入新结点  
void insert_1(Node *head, int i, int Newdate)  
{  
    Node *pre = head, *New = NULL;  
    int j = 0;  
    while(NULL != pre && j < i-1)  
    {   
          pre = pre->pstnext;  
          j++;  
    }  
    if(NULL == pre || j > i-1)  
    {  
          printf("插入位置不存在\r\n");  
    }
    else  
    {  
          New = (Node*)malloc(sizeof(Node));  
          if(NULL == New)  
          {  
               printf("分配内存失败\r\n");  
               return;  
          }  
          New->nDate = Newdate;  
          New->pstnext = pre->pstnext;  
          pre->pstnext = New;  
    }  
  
}  
//在指定元素之后插入新结点  
void insert_2(Node *head, int i, int Newdate)  
{  
    Node *pre = head, *New = NULL;  
    int j = 0;  
    while(NULL != pre->pstnext && j < i)  
    {  
          pre = pre->pstnext;  
          j++;  
    }  
    if( j == i)  
    {  
          New = (Node*)malloc(sizeof(Node));  
          if(NULL == New)  
          {  
              printf("分配内存失败\r\n");  
               return;  
          }  
          New->nDate = Newdate;  
          New->pstnext = pre->pstnext;  
          pre->pstnext = New;  
    }
    else  
    {  
          printf("插入位置不存在\r\n");  
    }  
}  
//删除指定结点  
void Delete_1(Node *head, int i3)  
{  
    Node *p = head, *pre = NULL;  
    int j = 0;  
    while(NULL != p && j < i3)  
    {  
          pre = p;  
          p = p->pstnext;  
          j++;  
    }  
    if(NULL == p)  
    {  
         printf("删除位置不存在\r\n");  
    }
    else  
    {  
          pre->pstnext = p->pstnext;  
          free(p);  
    }  
}  
//指定删除单链表中某个数据，并统计删除此数据的个数  
int Delete_2(Node *head, int Delete_date)  
{  
    int count = 0;  
    Node *p = head, *q;  
    while(NULL != p->pstnext)  
    {      
          q = p->pstnext;  
          if(q->nDate == Delete_date)  
          {  
               p->pstnext = q->pstnext;  
               free(q);  
               ++count;  
          }  
          else  
          {  
               p = q;  
          }  
}  
return count;  
}  
//链表逆置，一定要掌握好，详解见图 
void Reverse_list(Node *head)  
{  
    Node *q, *s;  
    if(NULL == head->pstnext || NULL == head->pstnext->pstnext)  //是否要判断head为空？
    {  
          return;  
    }  
    q = head->pstnext->pstnext;  
    head->pstnext->pstnext = NULL;  
    while(NULL != q)  
    {  
          s = q->pstnext;  
          q->pstnext = head->pstnext;  
          head->pstnext = q;  
          q = s;  
    }  
}  
//单链表的连接  
void connect_list(Node *head, Node *head_New)  
{  
    Node *p = head;  
    while(NULL != p->pstnext)  
    {      
          p = p->pstnext;  
    }  
    p->pstnext = head_New->pstnext;  
}  
//单链表销毁  
void destroy_list(Node* head)  
{  
    while (NULL != head)  
    {  
        Node* temp = head;  
          head = head->pstnext;  
          free(temp);  
    }  
}  
main()  
{  
int date, num;    //待查找数据  
int i3;     //指定删除元素的位置  
int i1, i2, Newdate_1, Newdate_2;    //待插入的新数据  
int Delete_date, k;    //待删除的数据与其个数  
Node *Head = NULL;   //定义头结点  
Node *Head_New = NULL;  
  
//链表建立  
Head = creat();  
printf("输出建立的单链表\r\n");  
output(Head);  
  
//单链表测长  
printf("单链表长度为\r\n");  
length(Head);  
  
//链表按值查找  
printf("请输入待查找的数据\r\n");  
scanf("%d", &date);  
    research_Date(Head, date);  
  
//链表按序号查找  
printf("请输入待查找序号\r\n");  
scanf("%d", &num);  
research_Number(Head, num);  
  
//在指定第i1个元素之前插入新元素Newdate  
printf("在指定第i个元素之前插入新元素Newdate");  
printf("请输入i与元素且以逗号间隔\r\n");  
scanf("%d,%d", &i1, &Newdate_1);  
insert_1(Head, i1, Newdate_1);  
printf("插入后新链表\r\n");  
output(Head);   
  
//在指定第i2个元素之后插入新元素Newdate  
printf("在指定第i个元素之后插入新元素Newdate");  
printf("请输入i与元素且以逗号间隔\r\n");  
scanf("%d,%d", &i2, &Newdate_2);  
insert_2(Head, i2, Newdate_2);  
printf("插入后新链表\r\n");  
output(Head);   
  
//指定删除i3元素  
printf("删除元素的位置\r\n");  
scanf("%d", &i3);  
Delete_1(Head, i3);  
printf("删除后新链表\r\n");  
output(Head);  
  
//指定删除单链表中某个数据，并统计删除此数据的个数  
printf("请输入待删除的元素\r\n");  
scanf("%d", &Delete_date);  
k = Delete_2(Head, Delete_date);  
printf("删除后新链表\r\n");  
output(Head);  
printf("删除指定元素在链表中的个数为：");  
printf("%d\r\n", k);  
  
//单链表逆置  
Reverse_list(Head);  
printf("逆置后输出\r\n");  
output(Head);  
  
//单链表的连接  
printf("建立一个新链表\r\n");  
Head_New = creat();  
printf("输出新链表");  
output(Head);  
printf("将新链表连接到原来链表的尾部并输出\r\n");  
connect_list(Head, Head_New);  
output(Head);  
         destroy_list(Head);  
  
}