c++ programming language

Write a recursive method that returns the number of 1s in the binary representation of n (an integer parameter to your method). Use the fact that the number of ones in n equals the number of 1s in the binary representation of n/2, plus 1, if n is odd. (Note that you don't add 1 ton/2. You add one to the number of 1s in the binary representation of n/2.) The answer for 25 would be 3, since the binary representation is 11001. For negative numbers, return the number of ones in the absolute value