Program to find your Day of Birth given Date of Birth

#include
#include
#include

main()
{
 clrscr();
 int d,m,y,year,month,day,i,n;
 printf("Enter how many times you want to run this program : ");
 scanf("%d",&n);
 for(i=1;i<=n;i++)
 {
 printf("

Enter the date : ");
 scanf("%d%d%d",&d,&m,&y);
 if( d>31 || m>12 || (y<1900 || y>=2000) )
  {
   printf("

INVALID INPUT
");
   getch();
   exit(0);
  }
 year = y-1900;
 year = year/4;
 year = year+y-1900;
 switch(m)
  {
   case 1:
   case 10:
   month = 1;
   break;
   case 2:
   case 3:
   case 11:
   month = 4;
   break;
   case 7:
   case 4:
  month = 0;
  break;
   case 5:
  month = 2;
  break;
   case 6:
  month = 5;
  break;
   case 8:
  month = 3;
  break;
   case 9:
   case 12:
  month = 6;
  break;
  }
 year = year+month;
 year = year+d;
 day  = year%7;
 switch(day)
  {
   case 0:
  printf("

Day is SATURDAY
");
  break;
   case 1:
  printf("

Day is SUNDAY
");
  break;
   case 2:
  printf("

Day is MONDAY
");
  break;
   case 3:
  printf("

Day is TUESDAY
");
  break;
   case 4:
  printf("

Day is WEDNESDAY
");
  break;
   case 5:
  printf("

Day is THURSDAY
");
  break;
   case 6:
  printf("

Day is FRIDAY
");
  break;
  }
}
 getch();
 return 0;
}