Find largest binary gap of a number N improved

Question

This is a follow-up question based on the original one. Could you please see the updated and refactored version and point at things to be improved in term of logic or efficiency?

I have now know as I have been made aware about the Greedy Algorithm; Math.Max and binary shifting which deal more gracefully with the task, however, if I were in a position to be unaware of them and this is the code I managed to write, what's your thoughts on it?

 public static int FindGap(int number)
 {
 string toBinary = Convert.ToString(number, 2);
 char[] toChar = toBinary.ToCharArray();
 char previous = '0';
 char current = '0';
 int maxGap = 0;
 int answer = 0;
 for (int i = 0; i < toChar.Length; i++)
 {
 if (toChar[i] == '1')
 {
 current = toChar[i];
 // keep last/latest largest gap as an answer
 if (answer < maxGap)
 {
 answer = maxGap;
 }
 // reset if 1 appeared and start counting next gap
 maxGap = 0;
 }
 if ((toChar[i] == '0' && current == '1') || (toChar[i] == '0' && previous == '0'))
 {
 current = '0';
 maxGap++;
 previous = current;
 }
 }
 if (answer != 0)
 {
 return answer;
 }
 else return 0;
 }

• Roland Illig: The code still creates a string although this is not needed. You should try the code from my answer on the previous question. It is much more efficient.
• AlexV: @RolandIllig: The OP states that yours and other suggestions are ignored on purpose. I'm not claiming that the justification is particularly reasonable.
• Kris: Long story short, I wanted to see my solution improved with the approach I have undertaken initially, without knowing what was already invented to support me in resolving such problems. It was important for me to see that I can do the Convert.ToString() inside the foreach loop and also that I have failed the obvious binary logic. To me that helps a lot.

Answer 1

If I were in a position to be unaware of them and this is the code I managed to write, what's your thoughts on it?

• No need to call ToCharArray() because you can iterate over the chars of a string as well
• By using an else if instead of the second if you won't need to check for toChar[i] == '0' but basically you only need a else.
• Using a foreach loop instead of a for loop seems more natural for this task.
• The returning of the answer can be simply return answer;
• Because ToString(int, 2) strips leading '0' you can remove both current and previous.

Summing up it could look like so

public static int FindGap(int number)
{
 int maxGap = 0;
 int answer = 0;
 foreach(var c in Convert.ToString(number, 2))
 {
 if (c == '1')
 {
 if (answer < maxGap)
 {
 answer = maxGap;
 }
 maxGap = 0;
 }
 else
 {
 maxGap++;
 }
 }
 return answer;
}

• Kris: Thanks a lot, I knew I was missing obvious things such as.. binary work, which translates to if and else.. This is exactly what I wanted, thanks a lot. I will work out all suggested ways of going about it, with Math.Max, binary shift and what @Roland Illig suggested. This is a great way for learning.