Unset the least significant bit

Given a binary number unset the rightmost set bit.

Algorithm: The biwise “&” of any number n with n-1 unsets the rightmost set bit e.g. 5=101 ,5-1=4=100 ,5&4=(101)&(100)=100(result with rightmost bit unset)

Implementation

def unset_rightmost(n)
    n&=(n-1)
end