Calculating the number of bits in a Subnet Mask in C#

Question

I have a task to complete in C#. I have a Subnet Mask: 255.255.128.0.

I need to find the number of bits in the Subnet Mask, which would be, in this case, 17.

Answer 1

A complete sample:

public int CountBit(string mask)
        {

            int ones=0;
            Array.ForEach(mask.Split('.'),(s)=>Array.ForEach(Convert.ToString(int.Parse(s),2).Where(c=>c=='1').ToArray(),(k)=>ones++));
          return ones

        }