#include<stdio.h>
#include<conio.h>
#include<iostream.h>
#include<string.h>

//============================================================================
struct crs
 {
    char name[20];
    int unit;
    float score;
 };
//============================================================================
struct stude
 {
   int id;
   char name[20];
   char family[30];
   int course_count;
   crs lession[10];
   char address[100];
 };
//=========================================================================
  int add_record(void);
  void print_log(stude x);
  stude search_by_id(int id);
  float cale_avg(stude x);
  int select_unit(int id);
  char menu(void);
//=========================================================================
void main ()
 {
   int i,x;
   stude s1;
   for(;;)
    {
      switch(menu())
	{
	  case '1':
	  i= add_record();
	  if (i==0)
	    cout<<"\n can not add record:";
	  break;


	 case '2':
	 cout<<"\n enter your ID :";
	 cin>>x;
	 i=select_unit(x);
	 if (i==0)
	 cout<<"\n can not add record:";
	 break;

	 case '3':
	 cout<<"\n enter your id: ";
	 cin>>x;
	 s1=search_by_id(x);
	 print_log(s1);
	 break;


	  case '4':
	  return;

	}// END switch
     }// End Of FOR
 }// ENd main
//=========================================================================
int add_record (void)
 {
   stude s1;
   FILE *f1;
   f1=fopen("stude.dat","a");
   if (f1==0)
     return(0);
   cout<<"\n enter stude ID: ";
   cin>>s1.id;
   cout<<"\n enter name :";
   gets(s1.name);
   cout<<"\n enter family :";
   gets(s1.family);
   cout<<"\n enter address: ";
   gets(s1.address);
   fwrite(&s1,sizeof(stude),1,f1);
   fclose(f1);

 }

//=========================================================================
 void print_log(stude x)
 {
   int i;
   float avg=cale_avg(x);
   cout<<"\n id ="<<x.id;
   cout<<"\n name ="<<x.name;
   cout<<"\n family ="<<x.family;
   cout<<"\n avg ="<<avg;
   for (i=0;i<x.course_count;i++)
   cout<<"\n   "<<x.lession[i].name<<"\t"<<x.lession[i].unit<<"\t"<<x.lession[i].score;
  }

//===========================================================================
stude search_by_id(int id)
 {
  stude s1;
   FILE *f1;
   f1=fopen("stude.dat","r");
   if (f1==0);
   {
     cout<<"can not open file";
     return(s1);
   }

  while (feof(f1)==0)
   {
     fread(&s1,sizeof(stude),1,f1);
     if (s1.id==id)
       {
	fclose(f1);
	return(s1);
       }//end if
   }//end while
  fclose(f1);
 }// end search

//===========================================================================
 float cale_avg(stude x)
 {
   int i;
   float sum=0,su=0;
   for(i=0;i<x.course_count;++i)
    {
      sum=sum+x.lession[i].score*x.lession[i].unit;
      su=su+x.lession[i].unit;
    }//ende for
  return(sum/su);
 }
//===========================================================================
int select_unit(int id)
 {
   FILE * f1;
   stude s1;
   f1=fopen("stude.dat","r+a");
   if(f1==0)
   return(0);
     while (feof(f1)==0)
      {
	fread(&s1,sizeof(stude),1,f1);
	  if(s1.id==id)
	  break;
      }//end while

   cout<<"\n\a enter Count of crs :";
   scanf("%d",&s1.course_count);
   for (int i=0;i<s1.course_count;++i)
     {
       cout<<"\n\a enter Crs name:";
       scanf("%s",s1.lession[i].name);
       cout<<"\n\a enter Crs unit:";
       scanf("%d",&s1.lession[i].unit);
       cout<<"\n\a enter Crs score:";
       scanf("%f",&s1.lession[i].score);
     }//end for

   fseek(f1,-1*sizeof(stude),SEEK_CUR);
   fwrite(&s1,sizeof(stude),1,f1);
   fclose(f1);
   return(1);

 }//ende select unit
//===========================================================================
char menu(void)
 {
   char ch;
   clrscr();

	gotoxy(20,4);
	printf("1) add_ record");

	gotoxy(20,6);
	printf("2) select_unit");

	gotoxy(20,8);
	printf("3) print_log");

	gotoxy(20,10);
	printf("4) Quit");

	gotoxy(20,14);
	printf("Enter Youe select :[1..4]");

	do
	 {
	    ch=getch();
	 }while ((ch<'1') || (ch>'4'));
	 return(ch);

 }// end menu