C program Calculation of simple interest

/* Calculation of simple interest */

/* Author gekay  Date: 25/05/2004 */

main( )
{
int   p, n ;
float   r, si ;
p = 1000 ;
n = 3 ;
r = 8.5 ;
/* formula for simple interest */
si = p * n * r / 100 ;
printf ( "%f" , si ) ;
}