C++ program for Conversion into Octal

#include <conio.h>
#include <stdio.h>
using namespace std ;
int main (  )
{
long int i , num , arr[100] ;
printf( "Enter any number to convert it into Octal " ) ;
scanf( "%ld",&num ) ;
for ( i = 0 ; num > 8 ; i++ )
{
arr[i] = num % 8 ;
num = num / 8 ;
}
printf ( "Octal conversion is \n " ) ;
printf("%d",num) ;
while ( i>0 )
{
printf ("%d",arr[i-1]);
i-- ;
}
return 0 ;
}