#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct student_info
{
	int id;
	char name[20];
	float cscore;
};
struct student students[50];
int count=0;
printf("****************???????***************");
printf("*                                           *");
printf("**              1.????                 **");
printf("**              2.????                 **");
printf("**              3.????                 **");
printf("**              4.????????         **");
printf("**              5.?????,???       **");
printf("**              6.?????????       **");
printf("****************~~~~~~~~~~~~~~***************");
int main()
{
int n;
system("cls")
char name[20];
int i=0;
FILE *fp;
if((fp=fopen("a.txt","w+"))==NULL)
{
	printf("can not open the file!");
	exit(0);
}
for(i=0;i<50;i++)
{
	fprintf(fp,"%d %s %d",students[i].id,students[i].name,students[i].cscore);
}
do
{
printf("?????????:1.?? 2.?? 3.?? 4.????????\n5.?????,??? 6.????????? 7.??\n");
scanf("%d",&n);
switch(n)
{
  case 1:
	      printf("???????????");
		  scanf("%s",students[i].name)
		  search_student(students,name);
		  break;
  case 2:
	      printf("??0???????????????\n");
	      do
	    {
	      printf("???????????:");
	      scanf("%d",&students[i],id);
	      printf("???????????:");
	      scanf("%s",students[i].name);
	      printf("???????????");
		  scanf("%f",&students[i].csore);
		  if(students[i].id!=0)
		  fprintf(fp,"%d %s %s",students[i].id,students[i].name,students[i].cscore);
		}while(students[i].id!=0);
		 fclose(fp);
         break;
  case 3:
  	      printf("???????????:");
  	      scanf("%d",&students[i].id);
  	      printf("???????????:");
  	      scanf("%s",students[i].name);
  	      printf("???????????:");
  	      scanf("%d",&students[i].cscore);
  	      modify_student(students,id,name,cscore);
          break;
  case 4:
  	      system("cls");
  	      int i,j
			 if((fp=fopen("a.txt","w+"))==NULL)
          {
	            printf("can not open the file!");
	            exit(0);
          }
          while(fscanf(fp,"%d %s %d",&students[i].id,&students[i].name,&students[i].cscore)!=EOF)
          {
          	i++;
		  }
		  fclose(fp);
		  printf("90????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=90)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("80????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=80&&students[j].cscore<90)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
  	      printf("70????:");
  	      for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=70&&students[j].cscore<80)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("60????:")
	      for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=60&&students[j].cscore<70)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("50????:");
		   for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=50&&students[j].cscore<60)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("40????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=40&&students[j].cscore<50)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("30????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=30&&students[j].cscore<40)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("20????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=20&&students[j].cscore<30)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("10????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=10&&students[j].cscore<20)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  printf("0????:");
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore>=0&&students[j].cscore<10)
		  	printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  	printf("\n");
		  }
		  for(j=0;j<i;j++)
		  if(students[j].cscore<0)
		  break;

  case 5:
  	         system("cls");
			 if((fp=fopen("a.txt","w+"))==NULL)
          {
	            printf("can not open the file!");
	            exit(0);
          }
          while(fscanf(fp,"%d %s %d",&students[i].id,&students[i].name,&students[i].cscore)!=EOF)
          {
          	i++;
		  }
		  fclose(fp);
		  int max,min,j;
		  for(j=0;j<i;j++)
		  {
		  	if(students[j].cscore<students)
		  }
		 
		 
		 
		 
		 
		 
		 
		 
		 
		 
		 
  case 6:
  	      system("cls");
			 if((fp=fopen("a.txt","w+"))==NULL)
          {
	            printf("can not open the file!");
	            exit(0);
          }
          while(fscanf(fp,"%d %s %d",&students[i].id,&students[i].name,&students[i].cscore)!=EOF)
          {
          	i++;
		  }
		  fclose(fp);
		  strcut student temp;
		  for(j=0;j<i-1;j++)
		  {
		  	for(u=0;u<i-1-j;u++)
		  	if(students[u].cscore<students[u+1].cscore)
		  	temp=students[u];
		  	students[u]=students[u+1];
		  	students[u+1]=temp;
		  }
		  for(j=0;j<i;j++)
		  printf("%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  break;
		 
	  int serach_student(struct student_info students[],char *name)
	  {
		     system("cls");
			 if((fp=fopen("a.txt","w+"))==NULL)
          {
	            printf("can not open the file!");
	            exit(0);
          }
          while(fscanf(fp,"%d %s %d",&students[i].id,&students[i].name,&students[i].cscore)!=EOF)
          {
          	i++;
		  }
		  fclose(fp);
		  int i,flag=0;
		  if(i==0)
		   {
			  printf("??????!\n");
			  return -1;
		   }
		  for(j=0;j<i;j++)
		  {
			  if(strcmp(name,students[j].name)==0)
				  flag=1;
		      if(flag)
		        {
			      printf("??: %s ??:%s c????:%f",students[j].id,students[j].name,students[j].cscore);
			      return j;
			    }
	      }
	      printf("????????!");
	      return -1;
      }

      int modify_student(struct student_info students[],int idcard,char *names,int cscores)
      {
      	     system("cls");
      	     int n,i,j;
			 if((fp=fopen("a.txt","w+"))==NULL)
          {
	            printf("can not open the file!");
	            exit(0);
          }
          while(fscanf(fp,"%d %s %d",&students[i].id,&students[i].name,&students[i].cscore)!=EOF)
          {
          	i++;
		  }
		  printf("1.??????????? 2.??????????? ???:\n");
		  scanf("%d",&n);
		  if(n==1)
		  {
		  	for(j=0;j<i;j++)
		  	{
		  		if(strcmp(names,students[j].name)==0)
		  		students[j].cscore=cscores;
			}
		  }
		  if(n==2)
		  {
		  	for(j=0;j<i;j++)
		  	{
		  		if(idcard==students[j].id)
		  		students[j].cscore=cscores;
			}
		  }
		  fp=fopen("a.txt","w");
		  for(j=0;j<i;j++)
		  {
		  	fprintf(fp,"%d %s %d",students[j].id,students[j].name,students[j].cscore);
		  }
		  fclose(fp);
	  }