Duffinian.java

import java.util.*;
public class Duffinian //It is a composite number so that it(a) is relatively prime to the sum of divisors(b) of n
{
	//sum of divisors of n
	static int sum_div(int n)// n=35
	{
		int div =0;
		for(int i =1; i<= Math.sqrt(n); i++)// i =1..5
		{
			if(n%i==0)// 35%5==0
			{
				div = div + i + (n/i); // div=36+5+7=48
			}
		}
		return div; // div =48
	}
	
	static int gcd(int a, int b)// a=35, b=48
	{
		int gcd = 1;
		for(int i = 1; i<= a && i<=b; i++)  // i=36 -> f
		{
			if(a%i==0 && b%i==0)// 35%35==0 && 48%35==0
				gcd=i;	// gcd =1		
		}
		return gcd; // gcd =1
	}
	
	public static void main(String[] args) 
{
 	Scanner sc = new Scanner(System.in);
	 System.out.println("enter number"); 
	 int a =sc.nextInt();  // n= 35
	int b = sum_div(a); // s = 48 

	System.out.println("sum of divisors :"+b);
		int gcd = gcd(a,b);
	System.out.println("gcd = "+gcd);

	if (gcd ==1) // ->t , if relatively prime
	System.out.println("Duffinian Number");

	else
	System.out.println("Not Duffinian Number");
	} 
 }