单链表C语言

#include<stdio.h>
#include<stdlib.h>
typedef int ElemType;
typedef struct slink
{
    ElemType data;
    struct slink *next;
} slink;

slink *creatlink(int n)
{
    slink *head,*p,*s;
    int i;
    if(n<1)
    {
        return NULL;
    }
    p=head=(slink *)malloc(sizeof(slink));
    for(i=1; i<=n; i++)
    {
        s=(slink *)malloc(sizeof(slink));
        scanf("%d",&s->data);
        p->next=s;
        p=s;
    }
    p->next=NULL;
    return head;
}

int getlen(slink *head)

{
    slink *p;
    int n;
    p=head->next;
    n=0;
    while(p!=NULL)
    {
        n++;
        p=p->next;
    }
    return n;
}
int getelem(slink *head,int i,ElemType *e)
{
    slink *p;
    int j;
    if(i<1)
    {
        return 0;
    }
    p=head->next;
    j=1;
    while(p!=NULL&&j<i)
    {
        p=p->next;
        j++;
    }
    if(p==NULL)
    {
        return 0;