P318_1112 将链表逆序排列，即将链头当链尾，链尾当链头

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <string.h>

#define LEN sizeof(STUDENT)

typedef struct
{
long snum;
char sname[10];
char ssex;
int sage;
struct STUDENT*next;
}STUDENT;

void print(STUDENT *head)
{
STUDENT *p1;
p1 = head;
while(p1!=NULL)
{
printf("snum:%ld",p1->snum);
printf("\nsname:");
puts(p1->sname);
printf("ssex:%c",p1->ssex);
printf("\nsage:%d\n",p1->sage);
p1 = p1->next;
}
}

STUDENT * input_student(int n)
{
STUDENT*p1,*p2,*head;
int i = 0;
for(i = 0;i< n;i++)
{
p1 = (STUDENT *)malloc(LEN);
printf("snum:");
scanf("%ld",&p1->snum);
printf("sname:");
getchar();
gets(p1->sname);
printf("ssex:");
scanf("%c",&p1->ssex);
printf("sage:");
scanf("%d",&p1->sage);
if(i==0) {p2 = head = p1;}
else
{
p2->next = p1;
p2 =p2->next;
}
p1 = (STUDENT *)malloc(LEN);
}//for
p2->next= NULL;
free(p1);
return head;
}

STUDENT *converse(STUDENT *head)
{
if((head==NULL) ||(head->next == NULL)) return head;
STUDENT *p1,*p2;
p1 = NULL;
while(head!=NULL)
{
p2 = head->next;
head->next = p1;
p1 = head;
head = p2;
}
head = p1;
return head;
}

int main()
{
int n;
printf("how manystudents' information you want to input:");//11题
scanf("%d",&n);
STUDENT *ahead =input_student(n);
printf("These arestudents'informations:\n");
print(ahead);
ahead =converse(ahead);
printf("These arestudents'informations concersed:\n");
print(ahead);
return 0;
}