#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>
#include<dos.h>
#include<string.h>
#include<mem.h>
#include<conio.h>
#include<GRAPHICS.H>
#include<time.h>

#define NULL 0
#define N 1000
#define M 1000
int k=0;
char buf[]="E\\DATE.TXT";

struct students
{
 int num1;
 char name[10];
 int chinese1;
 int english1;
 int math1;
 }stu[M];
 struct student
 {
   int mum;
   char num[10];
   int chinese;
   int english;
   int math;
   float ave;
   struct student *next;
   }stud[N];

   main()
   {
    struct student *creat();
    struct student *SQL();
    struct student *del();
    struct student *mode();
    struct student *insert();
    struct student *writeDat(struct student *);
    int readDat(struct student *);
    void print(struct student *);
    int readDat(void);
    void print(struct student *)
    void average();
    void free_lost();
    int far getbcolor();
    void textbackground();
    void textcolor();
    void textmode(int mode);


    int i;
    int j=0;
    int m;

    struct student *head;
    void textbackground(int red);
    int far getbcolor(void);
    void textcolor(int color);
    void textmode(int mode);

    time_t td;
    putenv("TZ=EST5EDT");
    tzset();
    time(&td);
    printf("current date and time is :%s\n",asctime(localtime(&td)));

    m=readDat();
    if(m)
      {
	head=creat(m);
	print(head);
      }
    printf("\nplease choose your chose:\n0.Exit 1 insert 2.Delect 3.findout 4.modefy 5.average 6.free\n");
    scanf("%d",&i);

    while(i!=0)
    {if(i==1)
       {head=insert(head);
	print(head);
	printf("\nplease choose your chose:\n0.exit 1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	scanf("%d",&i);
	 }
      if(i==2)
	{head=del(head);
	 print(head);
	 printf("\nplease choose your chose:\n0.exit.1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	 scanf("%d",&i);
	}

      if(i==3)
	{head=SQL(head);
	 print(head);
	 printf("\nplease choose your chose:\n0.exit 1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	 scanf("%d",&i);
	 }

      if(i==4)
	 {head=mode(head);
	  print(head);
	  printf("\nplease choose your chose:\n0.exit 1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	  scanf("%d",&i);
	 }

      if(i==5)
	 {head=average(head);
	  print(head);
	  printf("\nplease choose your chose:\n0.exit 1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	  scanf("%d",&i);
	 }
      else
	 if((i!=0)&&(i!=1)(i!=2)&&(i!=3)&&(i!=4)&&(i!=5)%%(i!=6)&&j<3))
	  {
	    printf("error choose!!!!!!!\n");
	    printf("\nplease choose your chose:\n0.exit 1.insert 2.delect 3.findout 4.modefy 5.average 6.free\n");
	    scanf("%d",&i);
	    j++;
	  }
	 }

       head=writeDat(head);
   }



   struct student *creat(int x)
     {
      int i;
      struct stduent *head,*p,*p1;
      head1=stud;
      for(p=head1,i=1;p<stud+x;i++)
	{
	  strcpy(p->name,stu->name1);
	  p->num=stu->num1;
	  p->chinese=stu->chinese1;
	  p->english=stu->english1;
	  P->math=stu->math1;
	  p1=p;
	  p->ave=(p->chinese+p->english+p->math)/3.0;
	  p->next=stud+i;
	  p=p->next;
	}
	p1->next=null;

	return(head1);
     }


     struct student *SQL(struct student *head)
       {
	struct student *p;
	int key;
	p=head;
	printf("\n please input student's number your want to kown:\n");
	scanf("%d",%key);
	while(p!=null)
	{
	  if(p->num==key)
	  {printf("\nNUMBER   NAME    CHINESE    ENGLISH    MATH    AVERAGE\N");
	   printf("%-10d%-10s  %-6.2d  %-6.2d  %-6.2d  %-6.2f\n",p->num,p->name,p->chinese,p->english,p->math,p->ave);
	   break;
	    }
	   else
	     p=p->next;
	  }
	if(p==null)
	 printf("\n DON'T HAVE SUCH A STUDENT!!\N");
	retrun(head);
     }


   struct stedent *del(struct stduent *head)
     {
       struct student *p,*back;
       int key;
       p=head;
       printf("\nplease input student's number you want to delect:/n");
       scanf("%d",&key);
       while(key!=0)
       {
	 if(p->next==NULL)
	  {printf("\nDON'T FOUND!!");break;}
	 if(head->num==key)
	  {head=p->next;
	   free(p);
	   break;
	   }
	  back=p;
	  p=p->nxet;
	  if(p->num==key)
	   {back->next=p->next;
	    free(p);break;}
	 }
	 return(head);
     }


     struct student *mode(struct student *head)
      {
	struct student *p;
	int key;
	p=head;
	printf("\nplease input student's number you want to modefy:\n");
	scanf("%d",&key);
	while(p!=NULL)
	 {
	   if(p->num==key)
	     {
	      printf("\nplease input student's old name or new name:\n");
	       scanf("%s",p->name);
	      printf("\nplease input student's chinese score(0~100):\n");
	       scanf("%d",&p->chinese);
	      while(p->chinese>100||p->chinese<0)
		{printf("\n ERROR!!!\nplease input student's chinese score(0~100):\n);
		 scanf("%d",&p->chinese);
		}
	      printf("\nplease input student's new english score(0~100):\n");
	       scanf("%d",&p->english);
	      while(p->english>100||p->english<0)
		{printf("ERROR!!!\nplease input student's english score(0~100):\n);
		 scanf("%d",&p->english);
		 }
	      printf("\nplease input student's new math score(0~100):\n);
	       scanf("%d",&p->math);
	      while(p->math>100||p->math<0)
		{printf("\nERROR!!!\nplease input student's math score(0~100):\n");
		  scanf("%d",&=->math);
		 }
	       p->ave=(p->chinese+p->english+p->math)/3.0;
	       break;
	      }
	  else
	     p=p->next;
	  if(p->next==NULL)
	    {printf("\nDON'T HAVE such a student!!\n");
	     break;
	     }
       }
       return(head);
    }



    struct student *insert(struct student *head)
     {
      struct student *p,*newstudent;
      p=head;
      newstudent=(struct student *malloc(sizeof(struct student));
      printf("\nplease input newstudent's number:");
      scanf("%d",&newstudent->num);
      while(p!=NULL)
	{
	 while(newstudent->num==p->num)
	  {printf("\nthese has been such a student,please input another:");
	   scanf("%d",*newstudent->num);
	  }
	  p=p->next;
	 }
      printf("\nplease input newstudent's name:");
      scanf("%s",newstudent->name);
      printf("\nplease input student's chinese score(0~100):\n");
       scanf("%d",&newstudent->chinese);
      while(newstudent->chinese>100||newstudent->chinese<0)
	 {printf("\nERROR!!!\nplease input student's chinese score(0~100):\n");
	  scanf("%d",&newstudnet->chinese);
	 }
      printf("\nplese input student's new english score(0~100):\n");
      scanf("%d",&newsstudnet->english);
      while(newstudent->english>100||newstudeht->english<0)
	{printf("\nERROR!!!!\nplease input student's english score(0~100):\n");
	 scanf("%d",&newstudent->english);
	}
      printf("\nplease input student's new math score(0~100):\n);
	scanf("%d",&newstudent->math);
      while(newstudeht->math>100||newstudent->math<0)
	 {printf("\nERROR!!!\nplease input student's math score:\n");
	  scanf("%d",*newstudent->math);
	 }
      newstudent->ave=(newstudent->chinese+newstudent->english+newstudent->math)/3.0;

      p=head;

      if(head->num>newstudent->num)
	{newstudent_>next=head;
	 head=newstudent;
	}
      else
	while(p!=NULL)
	 {if((p->num<newstudent->num&&newstudent->num<p->next)||p->next==NULL)
	   {newstudent->next=p->next;
	    p->next=newstudent;
	    break;
	    }
	   p=p->next;
	 }
       }
       return(head);
   }

   void print(struct student *head)
   {
    struct student *p;
    printf("\nNUMBER    NAME    CHINESE    MATH    AVERAGE\N");
    p=head;
    if(p!=NULL)
     {do
       {printf("%-10d%-10s%-6.2d  %-6.2d  %-6.2d  %-6.2f\n",p->num,p->name,p->chinese,p->english,p->math,p->ave);
	p=p->next;
       }
	while(p!=NULL)
      }


   void average(struct student *head)
   {
    int j;
    float sum;
    struct student *p;
    p=head;
    for(j=0,sum=0;p->next!=NULL;j++)
       {
	sum+=p->ave;
	p=p->next;
	free(p);
       }
    }


   struct student *writeDat(struct student *head)
   {
    FILE *fp;
    struct student *p;
    char savefile[10];
    p=head;
    if((fp=fopen(buf,"w"))==NULL)
      {printf("\ncan't open the DATE file!!\n");
       exit(0);
      }
    while(p!=NULL)
      {fprintf(fp,"%-10d%-10s%-6.2d  %-6.2d  %-6.2d  %-6.2f\n",p->num,p->name,p->chinese,p->english,p->math,p->ave);
       p=p->next;
      }
       fclose(fp);
     return(head);
   }


   int readDat(void)
   {FILE *fp;
    if((fp=fopen(buf,"a"))==NULL)
     {
      printf("\ncann't open savefile \n");
      exit(0);
     }
    else
      while(!feof(fp))
      {fread(&stu[k],sizeof(struct student),1,fp);
       k++;
      }
    fclose(fp);
    return(k);
 }