Given a number,check if it is power of 2 or not without using division or modulo operator.

Algorithm: For any power of 2,say x, the bitwise and of x and x-1 is always 0. e.g. 64 = 1000000, 63= 0111111 now 1000000&0111111==0000000

Implementation

def check_power(x)
    if x&(x-1)==0
        print "#{x} is power of two"
    else
        print "#{x} is not power of two"
    end
end
check_power(126) # => 126 is not power of two 
check_power(1024) # => 1024 is power of two