C Program Calculation of total expenses

/* Calculation of total expenses */
main( )
{
int   qty, dis = 0 ;
float   rate, tot ;
printf ( "Enter quantity and rate " ) ;
scanf ( "%d %f", &qty, &rate) ;
if ( qty > 1000 )
dis = 10 ;
tot = ( qty * rate ) - ( qty * rate * dis / 100 ) ;
printf ( "Total expenses = Rs. %f", tot ) ;
}