using System;

using System.Diagnostics;

using System.Collections.Generic;

​

public class Program {

    public static void Main() {

        Random r = new Random();

        for (int i = 0; i < 10000; i++) {

            var rndBase = r.Next(2, 62);

            var encoded = NumberToBase(i, rndBase);

            var decoded = NumberFromBase(encoded, rndBase);

            if (i != decoded) {

                Console.WriteLine("i: {0} enc: {1} dec: {2}", i, encoded, decoded);

            }

        }

        Console.WriteLine("Completed no errors");

    }

​

    // Define other methods and classes here

    private const string BASE_DIGITS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    /// <summary>

    /// Convert a base 10 number to a different base.

    /// </summary>

    /// <param name = "number">Number to convert</param>

    /// <param name = "toBase">Base to use</param>

    /// <returns>String</returns>

    public static string NumberToBase(long number, int toBase) {

        Debug.Assert(toBase >= 2 && toBase <= BASE_DIGITS.Length);

        if (number == 0) return "0";

        if (number < 0) throw new ArgumentOutOfRangeException("number", number, "Number cannot be negative");

        var baseChars = BASE_DIGITS.ToCharArray();

        var result = new Stack<char>();

        while (number != 0) {

            result.Push(baseChars[number % toBase]);

            number /= toBase;

        }

​

        return new string (result.ToArray());

    }

​

    /// <summary>

    /// Convert a string in a different base to a base 10 number

    /// </summary>

    /// <param name = "number">Number to convert</param>

    /// <param name = "fromBase">Base to convert from</param>

    /// <returns>Int64</returns>

    public static long NumberFromBase(string number, int fromBase) {

        Debug.Assert(fromBase >= 2 && fromBase <= BASE_DIGITS.Length);

        long result = 0;

        long multiplier = 1;

        for (var i = number.Length - 1; i >= 0; i--) {

            result += BASE_DIGITS.IndexOf(number[i]) * multiplier;

            multiplier *= fromBase;

        }

​

        return result;

    }

}