Write a programe to Calculation of simple interest in c language

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

void main( )
{
int p, n ;
float r, si ;
printf ( "Enter values of p, n, r" ) ;
scanf ( "%d %d %f", &p, &n, &r ) ;

si = p * n * r / 100 ;
printf ( "%f" , si ) ;
getch();
}