void end_money() {
 int m,minute,hour;
 char xuehao;
 printf("请输入学号:");
 scanf("%ld",&xuehao);
 for(m = 0; m < i; m++)
 {
   if(student[m].xuehao==xuehao)
  {
   printf("请输入%ld的下机时间:",xuehao);
   scanf("%d:%d",&student[m].end.hour,&student[m].end.minute);
   if(student[m].end.minute<student[m].begin.minute)
   {
    minute=student[m].end.minute+60
           -student[m].begin.minute;
    hour=student[m].end.hour-1-student[m].begin.hour;
    student[m].time_hour = hour;
    student[m].time_minute = minute;
   }
   else
   {
    minute=student[m].end.minute -student[m].begin.minute;
    hour=student[m].end.hour -student[m].begin.hour;
    student[m].time_hour = hour;
    student[m].time_minute = minute;

   }
   if(minute > 0)
   {
    hour = hour + 1;
    printf("上机时间为:%d:%d 费用为:%d",student[m].time_hour,student[m].time_minute,hour);
   }
    else {
    printf("上机时间为:%d:%d\n 费用为:%d",student[m].time_hour,student[m].time_minute,hour);
   }
  }
 }
         save();
 printf("\n");  system("pause");
 system("cls");
}
void select_xuehao() {
 long int xuehao;
 int m;
 printf("请输入学号:");
 scanf("%ld",&xuehao);
 for(m = 0; m < i; m++)
 {
  if(student[m].xuehao==xuehao)
  {
   printf("学号:%ld\t",student[m].xuehao);
   printf(" 班级:%s\t",student[m].banji);
   printf("姓名:%s\t",student[m].name);
   printf(" 上机开始时间:%d:%d\t",student[m].begin.hour,student[m].begin.minute);
   printf("上机结束时间:%d:%d\t",student[m].end.hour,student[m].end.minute);
   printf("上机时间:%d:%d\n\t",student[m].time_hour,student[m].time_minute);
  }
  else if( m == i)
  {
   printf("没有该生记录:\n");
  }
 }
save();
 printf("\n");  system("pause");
 system("cls");
}
void select_banji() {
 char banji[10];
 int m;
 printf("请输入班级:");
 scanf("%s",banji);
 for(m = 0; m < i; m++)
 {
  if(!strcmp(banji,student[m].banji)) {
   printf("学号是:%ld\t",student[m].xuehao);
   printf("班级是:%s\t",student[m].banji);
   printf("姓名是:%s\t",student[m].name);
   printf("上机开始时间:%d:%d\t",student[m].begin.hour,student[m].begin.minute);
   printf("上机结束时间:%d:%d\t",student[m].end.hour,student[m].end.minute);
   printf("上机时间为:%d:%d\n",student[m].time_hour,student[m].time_minute);
  }
 else if( m == i)
 {
 printf("没有该生记录:\n");
  }
 }save();
 printf("\n");  system("pause");
   system("cls");
}