using System;

​

public class Program

{

    private static readonly char[] base16Values = new char[16]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    private static char[] maxCharIntBase2 = new char[33];

    public static void Main()

    {

        for (int i = -20; i <= 100; i++)

        {

            for (int j = 2; j <= 16; j++)

            {

                Console.WriteLine("ITOA RESULT: " + itoa(i, j));

            }

        }

    }

​

    static string itoa(int value, int numericBase)

    {

        if (value == 0)

        {

            return "0";

        }

​

        if (numericBase < 2 || numericBase > 16)

        {

            Console.WriteLine("Attempted to convert an int to a string with a numeric base less than 2 or greater than 16");

            return "0";

        }

​

        int i = 33;

        bool isNegative = false;

        if (value < 0)

        {

            isNegative = true;

            maxCharIntBase2[--i] = base16Values[-(value % numericBase)];

            value = -(value / numericBase);

        }

​

        while (value > 0)

        {

            maxCharIntBase2[--i] = base16Values[value % numericBase];

            value /= numericBase;

        }

​

        if (isNegative)

        {

            maxCharIntBase2[--i] = '-';

        }

​

        return new string (maxCharIntBase2, i, 33 - i);

    }

}