编写函数删除链表中的结点，函数功能实现不了
编写insert函数，实现对上述链表结点的插入操作，编写delete函数，实现通过学号删除结点的操作，编写clear函数，实现对链表的清空操作。
#include "stdio.h"
#include "stdlib.h"
#define STUDENT struct student
#define LEN sizeof(STUDENT)
#define N 3
STUDENT
{
int num;
char name[20];
float score[3];
STUDENT *next;
};
float avg[N]={0.0};
float *average(STUDENT *head)
{
STUDENT *p;
int i=0;
p=head;
while(p!=NULL)
{
avg[i]=(p->score[0]+p->score[1]+p->score[2])/3;
p=p->next;
i++;
}
return avg;
}
STUDENT *create(int n)
{
STUDENT *head,*last,*p;
int i,j;
head=last=NULL;
for(i=0;i<n;i++)
{
p=(STUDENT *)malloc(LEN);
printf("\nplease input%d student's number,name:",i+1);
scanf("%d,%s",&p->num,&p->name);
printf("\nplease input score1 score2 score3:");
for(j=0;j<3;j++)
scanf("%f",&p->score[j]);
p->next=NULL;
if(i==0)
head=last=p;
else
{
last->next=p;
last=p;
}
}
return head;
}
void output(STUDENT *head)
{
STUDENT *p;
int i=0;
average(head);
p=head;
printf("\nnumber\tname\tscore1\tscore2\tscore3\taverage");
while(p!=NULL)
{
printf("\n%d\t%-s\t%.1f\t%.1f\t%.1f\t%.2f\n",p->num,p->name,p->score[0],p->score[1],p->score[2],avg[i]);
p=p->next;
i++;
}
}
STUDENT *insert(STUDENT *head,STUDENT *p)
{
STUDENT *p1,*p2;
p2=head;
if(head==NULL)//没有插入点
{
p->next=NULL;
head=p;
}
else//有插入点
{
while( p2!=NULL&&(p->num > p2->num))//查找插入点
{
p1=p2;
p2=p2->next;
}
if(p2==head)//插入点为第一个结点的位置
{
p->next=head;
head=p;
}
else//位于中间或末尾
{
p->next=p2;
p1->next=p;
}
}
return head;
}
STUDENT *delete(STUDENT *head,int num)
{
STUDENT *p1,*p2;
p2=head;
if(head==NULL)//如果链表为空
{
printf("\nList is null\n");
return head;
}
p2=head;
while(num!=p2->num && p2->next!=NULL)//查找删除结点
{
p1=p2;
p2=p2->next;
}
if(p2->next!=NULL)//如果不是链表的末尾，即找到了删除结点p2
{
if(p2==head)//删除的是第一个结点
head=p2->next;
else
p1->next=p2->next;
free(p2);
printf("\ndelete %d successfully",num);
}
else
printf("%d can't be found!",num);
return head;
}
void clear(STUDENT *head)
{
STUDENT *p,*p1;
p=head;
while(p!=NULL)
{
p1=p;
p=p->next;
free(p1);
}
}
main()
{
STUDENT *head;
STUDENT *p;
p=(STUDENT *)malloc(LEN);
int n,i;
char c;
do
{
printf("1.input student information\n");
printf("2.insert student information\n");
printf("3.delete student information\n");
printf("4.clear the information\n");
printf("5.quit\n");
printf("please choose");
c=getchar();
getchar();
if(c=='1')
{
printf("please input the amount of the students:");
scanf("%d",&n);
getchar();
head=create(n);
output(head);
}
else if(c=='2')
{
printf("please input the student's number,name:");
scanf("%d,%s",&p->num,&p->name);
printf("please input score1 score2 score3:");
for(i=0;i<3;i++)
scanf("%f",&p->score[i]);
insert(head,p);
printf("the new information is:");
output(head);
}
else if(c=='3')
{
printf("please input the number of the student you want to delete:");
scanf("%d",n);
delete(head,n);
printf("the new information is:");
output(head);
}
else if(c=='4')
{
clear(head);
//output(head);
}
else if(c=='5')
break;
getchar();
}while(c!='5');
printf("thank you for using this system!\n");
}
不知道为什么delete函数老是实现不了，而且运行时无法重复实现insert的功能，不知道哪里出问题了，请大家指点一下O(∩_∩)O
里面具体的步骤也不是很理解