Find position of set bit Java

PROGRAM TO FIND POSITION OF THE ONLY SET BIT

class MAIN {

  

    // A utility function to check whether n is a power of 2 or not.

    // See http://goo.gl/17Arj

    static boolean isPowerOfTwo(int n)

    {

        return (n > 0 && ((n & (n - 1)) == 0)) ? true : false;

    }

  

    // Returns position of the only set bit in 'n'

    static int findPosition(int n)

    {

        if (!isPowerOfTwo(n))

            return -1;

  

        int i = 1, pos = 1;

  

        // Iterate through bits of n till we find a set bit

        // i&n will be non-zero only when 'i' and 'n' have a set bit

        // at same position

        while ((i & n) == 0) {

            // Unset current bit and set the next bit in 'i'

            i = i << 1;

  

            // increment position

            ++pos;

        }

  

        return pos;

    }

  

    // Driver code

    public static void main(String[] args)

    {

        int n = 16;

        int pos = findPosition(n);

        if (pos == -1)

            System.out.println("n = " + n + ", Invalid number");

        else

            System.out.println("n = " + n + ", Position " + pos);

  

        n = 12;

        pos = findPosition(n);

        if (pos == -1)

            System.out.println("n = " + n + ", Invalid number");

        else

            System.out.println("n = " + n + ", Position " + pos);

  

        n = 128;

        pos = findPosition(n);

        if (pos == -1)

            System.out.println("n = " + n + ", Invalid number");

        else

            System.out.println("n = " + n + ", Position " + pos);

    }

}




OUTPUT:

n = 16, Position 5
n = 12, Invalid number
n = 128, Position 8

CREDITS: https://www.geeksforgeeks.org/find-position-of-the-only-set-bit/