#include<stdio.h>
#include<stdlib.h>
struct student
{
    int num;
    char name[20];
    struct student* next;
};
int main()
{
    struct student* head,*p,*ptr;
    struct student* creat();
    struct student m={4,"chenqi"};
    struct student* insert(struct student m,struct student* p,int n);
    int n=0;
    ptr=creat();
    insert(m,ptr,n);
    ptr=insert(m,ptr,n);
    while(ptr!=NULL)
    {
        printf("%d %s %p\n",ptr->num ,ptr->name ,ptr->next );
        ptr=ptr->next;
    }
    return 0;
}
struct student* creat()
{
    struct student *p1,*p2,*head;
    head=NULL;
    p1=p2=(struct student*)malloc(sizeof(struct student));
    int n=0;
    scanf("%d %s",&p1->num,&p1->name);
    while(p1->num!=0)
    {
        n=n+1;
        if(n==1)head=p1;
        else p2->next=p1;
        p2=p1;
        p1=(struct student*)malloc(sizeof(struct student));
        scanf("%d %s",&p1->num,&p1->name);
    }
    p2->next=NULL;
    return head;
}
struct student *insert(struct student m,struct student *p,int n)
{
    int i;
    struct student *p1,*p2,*p3;
    p3=p;
    p1=&m;
    for(i=0;i<n;i++)
    p3=p3->next ;
    p2=p3->next ;
    p3->next =p1;
    p1->next=p2;
    return p;
}

虽然写得不是很规范，而且有几个没有用的变量没删，但主要问题是函数传入地址问题。
就是函数传入参数能不能改变主函数里参数的值的问题~帮你修改了很多了，至于插入，留在了尾部，这个可以改。

#include<stdio.h>
#include<stdlib.h>
struct student
{
    int num;
    char name[20];
    struct student* next;
};
int n=0;//n最好用全局变量
int main()
{
    struct student *ptr;//多余的变量去掉
    struct student* creat();
    struct student m={4,"chenqi",NULL};
    void insert(struct student *m,struct student* p);//不用加返回值，用void就行了
    ptr=creat();
    insert(&m,ptr);//注意，传入的是m的地址，不是m~
    while(ptr!=NULL)
    {
        printf("%d %s %p\n",ptr->num ,ptr->name ,ptr->next );
        ptr=ptr->next;
    }
    return 0;
}
struct student* creat()
{
    struct student *p1,*p2,*head;
    head=NULL;
    p1=p2=(struct student*)malloc(sizeof(struct student));
    scanf("%d%s",&p1->num,&p1->name);
    while(p1->num!=0)
    {
        n=n+1;
        if(n==1)head=p1;
        else p2->next=p1;
        p2=p1;
        p1=(struct student*)malloc(sizeof(struct student));
        scanf("%d%s",&p1->num,&p1->name);
    }
    p2->next=NULL;
    return head;
}
void insert(struct student *m,struct student *p)
{
    int i;
    struct student *p3;
    p3=p;
    for(i=0;i<n-1;i++)
        p3=p3->next;
    p3->next =m;
    m->next=NULL;
}

插入别的位置改哪几个地方呢？我自己试了一下该不出来...先谢谢大佬的耐心解答！

[此贴子已经被作者于2016-11-21 07:49编辑过]