单链表的基本操作

#动态单链表的基本操作

#include<stdio.h>
#include<stdlib.h>
struct node 
{
    int data;
    struct node *next;
};
typedef struct node *linklist;
//头插法生成链表
void  createlist (linklist *head , int n)
{
    linklist p , s;
    int i;
    //srand(time(0));
    *head = (linklist) malloc(sizeof(struct node));
    (*head)->next = NULL;
    for (i = 0 ; i < n ; i ++)
    {
        p = (linklist)malloc(sizeof(struct node));
        p->data = i;
        p->next = (*head)->next;
        (*head)->next = p;
    }

}
//尾插法生成链表
void createtaillist (linklist *head , int n)
{
    linklist p , r;
    int i ;
    *head = (linklist)malloc(sizeof(struct node));
    r = *head;
    for (i = 0 ; i < n ; i ++)
    {
        p = (linklist)malloc(sizeof(struct node));
        p ->data = i;
        r ->next = p;
        r = p;
    }
    r ->next = NULL;
}
//单链表的插入 在第i个元素前插入元素
int listinsert (linklist *head , int i , int x)
{
    int j;
    linklist p , s;
    p = *head;
    j = 1;
    while (p && j < i)
    {
        p = p ->next;
        ++ j;
    }
    if (!p || j > i) return 0;
    s = (linklist)malloc(sizeof(struct node));
    s ->data = x;
    s ->next = p ->next;
    p ->next = s;
    return 1;
}
void printlist (linklist head)
{
    linklist p ;
    if (!head) return ;
    for (p = head ->next ; p != NULL; p = p ->next) printf("%d\n",p->data);
}
//单链表的结点删除
int deletelist (linklist *head ,int i)
{
    int j = 1;
    linklist p , temp;
    p = *head;
    //用 p ->next 是因为删除这个结点是需要这个结点的前一个结点
    //指向这个结点的后一个结点。
    while (p ->next && j < i) 
    {
        p = p ->next;
        ++ j;
    }
    if (!(p ->next) || j > i) return 0;
    temp = p ->next;
    p ->next = temp ->next;
    free(temp);
    return 1;
}
//单链表的整表删除
void freelist (linklist *head)
{
    linklist p = (*head)->next , temp;
    while (p)
    {
        temp = p ->next;
        free(p);
        p = temp;
    }
    (*head) ->next = NULL;
}
int main()
{
    int i , x;
    linklist head = NULL;
    //createlist(&head , 10);
    //for (i = 0 ; i < 1 ; i ++) add(&head , i);
    createtaillist(&head , 10);
    freelist(&head);
    printlist(head); 
    puts("");
    //for (i = 1 ; i < 6 ; i ++)
    //{
    //    listinsert(&head , i + i , 100);
    //}
    deletelist (&head , 2);
    printlist(head); 
    return 0;
}