#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <conio.h>

#include <string.h>

#define LEN sizeof(struct student) // 结构的长度

struct student creat(); // 建立链表
void print(struct student head); // 打印链表
struct student del(struct student head,int num); // 删除一个节点

struct student
{
int num;
float score;
struct student next;
};
int n,temp; // 全局变量
void main()
{
struct student stu,p;
int m;
stu=creat();
p=stu;
print(stu);
do
{
printf("please enter the num to delete:");
scanf("%d",&m);
print(del(p,m));
}while(m);
system("pause");
}
struct student creat()
{
struct student p1,p2,head;
p1=p2=(struct student )malloc(LEN);
printf("please enter the num:");
scanf("%d",&p1->num);
printf("please enter the score:");
scanf("%f",&p1->score);
head=NULL;
n=0;
while(p1->num)
{
n++;
if(n==1) // 判断是否删除第一个节点
{
head = p1;
}
else
{
p2->next=p1;
}
p2=p1;
p1=(struct student *)malloc(LEN);
printf("please enter the num:");
scanf("%d",&p1->num);
printf("please enter the score:");
scanf("%f",&p1->score);

};
void print(struct student head)
{
struct student p;
p=head;
printf("\nThere are %d records\n\n",n);
if(head)
{
do
{
printf("The num.%d score is %f\n",p->num,p->score);
p=p->next;
}
while(p);
}
}
struct student del(struct student head,int num)
{
struct student p1,p2;
if(head == NULL)
{
printf("An empty list\n");
goto end;
}
p1=head;
while(num != p1->num && p1->next != NULL)
{
p2=p1;
p1=p1->next;
}
if(p1->num == num)
{
if(p1==head)
{
head=p1->next;
}
else
{
p2->next=p1->next;
}
printf("Delete No.%d succeed\n",num);
n=n-1;
}
else

end:
return head;
};
为什么删除节点的时候，如果不删除第一个节点就没事，如果删除了第一个节点，后面输入什么，都会自动生成第一个节点。

第一个节点自动生成

不输入第一个节点，则无碍，请求大佬解答！万分感谢！

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