find the index of the highest bit set of a 32-bit number without loops obviously

Question

Here\'s a tough one(atleast i had a hard time :P):

find the index of the highest bit set of a 32-bit number without using any loops.

Answer 1

Let n - Decimal number for which bit location to be identified start - Indicates decimal value of ( 1 << 32 ) - 2147483648 bitLocation - Indicates bit location which is set to 1

public int highestBitSet(int n, long start, int bitLocation)
{
    if (start == 0)
    {
        return 0;
    }
    if ((start & n) > 0)
    {
        return bitLocation;
    }
    else
    {
        return highestBitSet(n, (start >> 1), --bitLocation);
    }
}

    long i = 1;
    long startIndex = (i << 31);
    int bitLocation = 32;
    int value = highestBitSet(64, startIndex, bitLocation);
    System.out.println(value);