读取文本信息，利用链表排序后输出

/*
功能：从文件中读入数据（文件为存储学号和姓名的文本，且学号和姓名在同一行，中间有空格），排序后输出到student_mass.txt
文件名：sort.c
作者：flonlen
*/

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

/*********  定义链表结点的具体内容  ***********/
typedef struct _student
{
	char stu_id[20];
	char name[20];
	struct _student *prov;
	struct _student *next;
}student,*stu;

/*********  函数功能：初始化头结点  ***********/
void init_head(stu list)
{
	list->next = list;
	list->prov = list;
}

/*********  函数功能：插入结点  ***********/
void list_add(stu node,stu prov,stu next)
{
	node->next = next;
	node->prov = prov;
	prov->next = node;
	next->prov = node;
}

/******  函数功能：将文件内容导入链表  *******/
void read_to_list(stu head)
{
	FILE *fp;
	int i ,j;
	stu node;
	char file_name[20],stu_mass[40] ,name[20];
	printf("请输入要打开的文件名：");
	scanf("%s",file_name);
	fp = fopen(file_name,"r");
	while(!feof(fp))
	{
		node = (stu)malloc(sizeof(student));
		i = 0,j = 0;
		fgets(stu_mass,40,fp);
		while(stu_mass[i] != ' ')
		{
			i++;
			j++;
		}
		while(stu_mass[j] == ' ')
		{
			j++;
		}
		strcpy(node->stu_id,stu_mass);
		node->stu_id[i] = '\0';
		i = 0;
		while(name[j] != '\0')
		{
			name[i] = stu_mass[j];
			if(name[i] == '\n')
				name[i] = '\0';
			j++;
			i++;
		}
		strcpy(node->name,name);
		list_add(node,head,head->next);
	}
	fclose(fp);
}

/***********  函数功能：定位第i个节点  **************/
stu pos_node(stu head,int i)
{
	stu temp;
	int j;
	temp = head->next;
	for(j = i;j > 1;j--)
		temp = temp->next;
	return temp;
}

/******  函数功能：节点交换  *******/
void exch_node(stu node1,stu node2)
{
	stu temp1,temp2;
	if(node1->next == node2)
	{
		temp1 = node1->prov;
		temp2 = node2->next;
		node1->next = temp2;
		node1->prov = node2;
		temp2->prov = node2;
		node2->prov = temp1;
		node2->next = node1;
		temp1->next = node2;
	}
	else
		if(node2->next == node1)
		{
			temp1 = node2->prov;
			temp2 = node1->next;
			node2->next = temp2;
			node2->prov = node1;
			temp2->prov = node2;
			node1->prov = temp1;
			node1->next = node2;
			temp1->next = node1;
		}
		else
		{
			temp1 = node2->next;
			temp2 = node2->prov;
			node1->next->prov = node2;
			node1->prov->next = node2;
			node2->next = node1->next;
			node2->prov = node1->prov;
			node1->prov = temp2;
			node1->next = temp1;
			temp1->prov = node1;
			temp2->next = node1;
		}
}

/*******  函数功能：排序  *******/
void sort(stu head)
{
	stu temp;
	int num = 0,i,j;
	double jindu;
	long jishu=0;
	temp = head->next;
	while(temp != head)
	{
		num++;
		temp = temp->next;
	}
	printf("排序中，请稍后。。。\n");
	for(i = 1;i < num+1;i++)
	{
		jindu = ((double)(i+1))/num;
		printf("\r已完成：%.1lf%%",jindu*100);		//排序进度
		for(j = i;j < num+1;j++)
		{
			if(strcmp(pos_node(head,i)->stu_id,pos_node(head,j)->stu_id) > 0)
			{
				exch_node(pos_node(head,j),pos_node(head,i));
			}
		}
	}
	printf("完成排序。\n");
}

/**********  函数功能：排序输出到文件  ***********/
void write_to_txt(stu head)
{	
	FILE *fp;
	stu temp;
	temp = head->next;
	fp = fopen("student_mass.txt","w+");
	while(temp != head)
	{
		fwrite(temp->stu_id,strlen(temp->stu_id),1,fp);
		fputc('    ',fp);
		fwrite(temp->name,strlen(temp->name),1,fp);
		fputc('\n',fp);
		temp = temp->next;
	}
	fputc('\n',fp);
	fclose(fp);
}

/*********  函数功能：查找学生信息并输出该学生的具体信息  ***********/
void search_stu(stu head)
{
	char act,sea_mass[20];
	stu temp;
	getchar();
	temp = head->next;
ACTION:
	printf("按姓名查找请输入1，按学号查找请输入2,退出请输入3：");
	act = getchar();
	if(act == '1')
	{
		printf("请输入要查找的姓名：");
		scanf("%s",sea_mass);
		getchar();
		while(strcmp(temp->name,sea_mass) != 0)
		{
			temp = temp->next;
			if(temp == head)
			{
				printf("没找到该学生，请检查是否输入有误！\n");
				goto ACTION;
			}
		}
	}
	else
		if(act == '2')
		{
			printf("请输入要查找的学号：");
			scanf("%s",sea_mass);
			getchar();
			while(strcmp(temp->stu_id,sea_mass) != 0)
			{
				temp = temp->next;
				if(temp == head)
				{
					printf("没找到该学生，请检查是否输入有误！\n");
					goto ACTION;
				}
			}
		}
		else
			if(act == '3')
			{
				exit(0);
			}
			else
			{
				printf("输入错误，请重新输入。\n");
				goto ACTION;
			}
		printf("姓名：%s,学号：%s\n",temp->name,temp->stu_id);
		goto ACTION;
}

/******  主函数  *******/
int main(int argc,char *argv[])
{
	stu head;
	head = (stu)malloc(sizeof(student));
	init_head(head);
	read_to_list(head);
	sort(head);
	write_to_txt(head);
	search_stu(head);
	return 0;
}