C program to check whether the entered number is Evil number or not.

 What do you mean by an EVIL number?

 An Evil number is a  number that has an even number of 1's in its binary expansion.

An Evil number is an non-negative number.

For example 9 is an Evil number. 

because binary expansion of number 9 is = 1001

and binary expansion 1001 has 2 number of 1's

since 2 is an even number ; We can say the number 9 is an EVIL number. 

Similarly number 3,6,15 are examples of EVIL number.

C Program

#include<stdio.h>

void IsEvil(int number);
int main()
{
    int n,num,B=0,rem,base=1;
    printf("Enter an Integer number : ");
    scanf("%d",&n);
    num = n;
    while (n > 0)
    {
        rem = n % 2;
        B = B + rem * base;
        base = base * 10;
        n = n / 2;
    }
    printf("Binary representation of %d is : %d",num,B);
    IsEvil(B);
    return 0;
}
void IsEvil(int number)
{
    int count=0,r;
    while(number > 0)
    {
        r = number % 2;
        if (r == 1)
        {
            count = count + 1;
        }
         number = number / 10;
    }
    printf("\nNumber of 1's  = %d",count);
    if (count % 2 == 0)
    {
        printf("\nThe number you entered is an EVIL number.");
    }
    else
    {
        printf("\nThe number you entered is NOT an EVIL number.");
    }
}

INPUT && OUTPUT