Write a program to find the given number is Armstrong number or not with the help of a recursive function.

Armstrong number is a number that is equal to the sum of digits raised to the power as length of the number.

```
import java.io.*;
public class armnum
{
static double n;int l;
void armnum(int nn)
{
n=nn;
String str=Double.toString(n);
l=str.length();
}
double sum_pow(double i)
{
if(i==0)
return 0;
else
{
double d=i%10;
double sum=Math.pow(d,l);
return(sum+sum_pow(i/10));
}
}
void isarmstrong()
{
if(sum_pow(n)==n)
System.out.println("armstrong number");
else
System.out.println("not armstrong number");
}
public static void main()throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("enter the number");
double n=Double.parseDouble(br.readLine());
armnum obj=new armnum();
obj.isarmstrong();
}
}
```