EVIL NUMBER

EVIL NUMBER:
       In number theory, an evil number is a non-negative number that has an even number of 1s in its binary expansion.

The first evil numbers are:

0, 3, 5, 6, 9, 10, 12, 15, 17, 18, 20, 23, 24, 27, 29, 30, 33, 34, 36, 39 .

These numbers give the positions of the zero values in the Thue–Morse sequence.

Numbers that are not evil are called odious numbers.

/* program to check given number is evil number or not*/

import java.io.*;

public class EvilNumber

{

    public static void main(String args[])throws IOException

    {

        int num, a, count , c, i;

        int binNum[] = new int[20];

        InputStreamReader in = new InputStreamReader(System.in);

        BufferedReader br = new BufferedReader(in);

        System.out.println("Enter a number:");

        num = Integer.parseInt(br.readLine());

        count = 0;  // count the number of 1's

        c = 0;      // for index of array

        while(num!=0)

        {

            a = num % 2;

            binNum[c] = a;

            if(a == 1)

             count++;

            num = num / 2;

            c++;

        }

        System.out.println("Total number of 1 is = " + count);

        // Print the binary number

        for(i=c-1; i>=0 ; i--)

        {

            System.out.print(binNum[i]+" ");

        }

        // Checking the number is Evil or Not

        if(count % 2 == 0)

        {

            System.out.println("\nEntered number is Evil an Number");

        }

        else

        {

            System.out.println("\nEntered number is not an Evil Number");

        }

    }   

}

OUTPUT:

Enter a number:

10

Total number of 1 is = 2

1 0 1 0 

Entered number is Evil an Number

Enter a number:

13

Total number of 1 is = 3

1 1 0 1 

Entered number is not an Evil Number