C语言实现顺序链表的创建和删除插入元素

#include<stdio.h>
#include<malloc.h>
#define LEN sizeof(struct student)
/*
	顺序链表的创建、删除、插入操作
*/
struct student{
	int num;
	float score;
	struct	student *next;
};
int n;

struct student *creat(){//创建链表;
	struct student *head;//头结点
	struct student *p1,*p2;
	p1=p2=(struct student *)malloc(LEN);//分配内存

	printf("\n请输入学号\n");
	scanf("%d",&p1->num);
	printf("\n请输入分数\n");
	scanf("%f",&p1->score);

	head=NULL;
	n=0;

	while(p1->num){
		n++;
		if(n==1){
			head=p1;
		}else{
			p2->next=p1;
		}
		p2=p1;

		p1=(struct student *)malloc(LEN);
		printf("\n请输入学号");
		scanf("%d",&p1->num);//输入为0则条件为0停止循环
		printf("\n请输入分数");
		scanf("%f",&p1->score);
	}
	p2->next=NULL;
	return head;
}

void print(struct student *head){//输出链表
	struct student *p;//定义指针
	p=head;//指针传递
	if(head){
		do{
			printf("\n学号为%d的成绩是:%f\n",p->num,p->score);
			p=p->next;
		}
		while(p);
	}
	printf("\n共有%d个数据\n",n);
}
struct student *del(struct student *head,int num){//删除元素
	struct student *p1,*p2;
	if(head==NULL){
			printf("\n空表\n");
			goto END;
	}else{
		p1=head;
		while(num!=p1->num&&p1->next!=NULL){//不是表尾节点
			p2=p1;
			p1=p1->next;
            }
		if(p1->num==num){
			if(p1==head){//判断是否为头结点
                   head=p1->next;//删除头结点
			}
			else{
                p2->next=p1->next;
			}
			printf("\n删除%d成功",num);
			n=n-1;
		}
		else{
			printf("\n不存在的数据\n");
		}

	}
END:
	return head;
}
//*head是链表的头指针

struct student *insert(struct student *head,struct student *stu_2){//第一个参数需要被插入的链表，第二个参数是插入的结构的地址
	struct student *p0,*p1,*p2;//p0指向待插节点,p1p2遍历
	p1=head;
	p0=stu_2;
	if(head==NULL){
		head=p0;
	}
	else{
		while((p0->num>p1->num)&&(p1!=NULL)){//开始条件为待插节点大于p0，结束条件为p1指向NULL
			p2=p1;//p2跟随p1
			p1=p1->next;//p1后移
			if(p0->num<=p1->num){
				if(p1==head){//p1若指向头结点
					head=p0;//插到表头之前
				}else{//插到表间
				p2->next=p0;
				}
				p0->next=p1;
			}else{//p0->num大于表中num
				p1->next=p0;//插到表尾
				p0->next=NULL;
			}
		}
	}
	n=n+1;
	return head;
}
int main(){
	struct student *stu,stu2,*p;
	int a;

	stu=creat(stu);
	p=stu;

	print(p);
    printf("\n");
    printf("请输入要删除学生的学号\n");
    scanf("%d",&a);
	print(del(p,a));


	printf("请输入要插入学生的学号\n");
	scanf("%d",&stu2.num);
	printf("请输入分数\n");
	scanf("%f",&stu2.score);
	print(insert(p,&stu2));

	system("pause");
return 0;
}