C program to create student information system of 10 students in the file

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

 struct student
 { char name[20];
   int rollno;
 }st[10];
 void main()
 {int var,i;
  char ch='y';
  FILE *pk=fopen("student.txt","w");
  clrscr();
  if(pk==NULL)
  { printf("\n FILE DOES NOT EXIST ");
    getch();
    exit(0);
  }
  while(ch=='y')
  { printf("\n Enter records:\n");
    for(i=0;i<10;i++)
    {
      printf("\n Enter name: ");
      scanf("%s",st[i].name);
      printf("\n Enter roll no.: ");
      scanf("%d",&st[i].rollno);
      fprintf(pk," %s %d\n",st[i].name,st[i].rollno);
    }
    printf("\n\n Do you want to continue(yes-Y): ");
    fflush(stdin);
    scanf("%c",&ch);
  }
  fclose(pk);
  clrscr();
  pk=fopen("student.txt","r");
  for(i=0;i<=9;i++)
  {fscanf(pk,"%s%d",st[i].name,&st[i].rollno);
   printf("\n\n Name: %s\n Roll no.: %d",st[i].name,st[i].rollno);
  }
  getch();
  fclose(pk);
 }