创建链表，输入n个学生数据，按成绩降序输出学生信息，并输出需要补考的学生信息

思路：

1.构建插入链表，将输入的数据按成绩插入，成绩高的插入在前；

2.构建输出链表，按顺序输出链表信息；

3.构建删除链表，将高于60分的不用补考的学生信息删除。

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

struct student
{
	char name[10];
	float score;
	struct student* next;
};

void print(struct student* head)
{
	struct student* p = head;
	while (p != NULL)
	{
		printf("%s %.1f\n", p->name, p->score);
		p = p->next;
	}
}

struct student* insert(struct student* head)
{
	struct student* p, * pnew, * pold=NULL;
	pnew = (struct student*)malloc(sizeof(struct student));
	scanf("%s%f", pnew->name, &pnew->score);
	p = head;
	if (pnew->score > head->score)
	{
		pnew->next = head;
		head = pnew;
	}
	else
	{
		while (p != NULL && pnew->score < p->score)
		{
			pold = p;
			p = p->next;
		}
		pnew->next = p;
		pold->next = pnew;
	}
	return head;
}

struct student* pdelete(struct student* head, int grade)
{
	struct student* p, * pold;
	p = head;
	while (head != NULL && head->score >= grade)
	{
		head = head->next;
		free(p);
		p = head;
	}
	if (head == NULL)
		return head;
	p = head->next;
	pold = head;
	while (p != NULL)
	{
		if (p->score >= grade)
		{
			pold->next = p->next;
			free(p);
			p = pold->next;
		}
		else
		{
			pold = p;
			p = p->next;
		}
	}
	return head;
}

int main()
{
	struct student* head;
	int i,n;
	printf("input the number of nodes:\n");
	scanf("%d", &n);
	printf("plese input the students' names and scores:\n");
	head = (struct student*)malloc(sizeof(struct student));
	scanf("%s%f", head->name, &head->score);
	head->next = NULL;
	for (i = 1; i < n; i++)
		head = insert(head);
	printf("\noutput all nodes:\n");
	print(head);
	head = pdelete(head, 60);
	printf("\noutput fail-nodes:\n");
	print(head);
	return 0;
}