初始化带头结点的单链表；输出带头结点单链表。

帮你做一题吧，大家都不容易。
/*建立一个整数链表*/
#include <stdio.h>
#include <stdlib.h>
struct chain
{
int value;
struct chain *next;
};
struct chain *create()
{
struct chain *head, *tail, *p;
int x;
head = tail = NULL;
printf("Input data.\n");
while (scanf("%d",&x) == 1) /*如果输入的是整型数据，那么向下执行，要退出输入，输入非整数即可*/
{
p = (struct chain *)malloc (sizeof (struct chain));
/*首先为要新创建的表元p开辟一个内存空间*/
p->value = x;
p->next = NULL;
if(head == NULL)
head = tail = p;
else
/*tail为倒数第二个表元指针，tail->始终指向最后一个表元*/
tail = tail ->next;
tail ->next = p;
}
return head;
}

main(){
struct chain *p,*q;
q = create();
while(q) {
printf("%d\n",q->value);
p = q->next;
free(q);
q = p;
}
system("pause");
}