WAP to Calculation of simple interest

/*WAP to Calculation of simple interest */

#include<stdio.h>
#include<conio.h>
main( )
{
 int   p, n ;
 float   r, si ; 

 p = 1000 ;
 n = 3 ;
 r = 4.5 ;

 /* formula for simple interest */
 si = p * n * r / 100 ;  

 printf ( "%f" , si ) ;
}