using System;

namespace TranslateToAnotherSystem
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("A number system is determined by the number of characters available for representing numbers.");
            Console.WriteLine("Choose a number system:");
            Console.WriteLine("1- 2nd \n2- 8th \n3- 10th \n4- 16th");
            Console.Write("Insert the option here: ");
            int system = Convert.ToInt32(Console.ReadLine());
            Console.Write("Enter a number: ");
            string s = Console.ReadLine();
            Console.WriteLine("Processing ... ");
            switch (system)
            {
                case 1:
                    {
                        Console.WriteLine("Binary system accepted. ");
                        Console.WriteLine("Result8 is:"+FromTwoToEight(s));
                        Console.WriteLine("Result10 is:" + FromNToTen(s,2));
                        Console.WriteLine("Result16 is:" + FromTwoToSixteen(s));
                        break;
                    }
                case 2:
                    {
                        Console.WriteLine("You've chosen ");
                        string result10 = Convert.ToString(FromNToTen(s, 8));
                        string result2 = FromTenToTwo(result10);
                        Console.WriteLine("Result2 is:" + result2);
                        Console.WriteLine("Result10 is:" + result10);
                        Console.WriteLine("Result16 is: " + FromTwoToSixteen(result2));
                        break;
                    }
                case 3:
                    {
                        Console.WriteLine("You've chosen deciminal system.\nPlease, wait for a minute, we are workin' on it. ");
                        Console.WriteLine("Result2 is: " + Convert.ToString(FromNToTen(s, 2)));
                        Console.WriteLine("Result8 is: "+ Convert.ToString(FromNToTen(s,8)));
                        Console.WriteLine("Result16 is: "+ Convert.ToString(FromNToTen(s,16)));
                        break;
                    }
                case 4:
                    {
                        Console.WriteLine("You've chosen ");
                        string result10 = Convert.ToString(FromNToTen(s, 16));
                        string result2 = FromTenToTwo(result10);
                        Console.WriteLine("Result2 is:" + result2);
                        Console.WriteLine("Result8 is: " + FromTwoToEight(result2));
                        Console.WriteLine("Result10 is:" + result10);
                        break;
                    }
                default:
                    {
                        Console.WriteLine("Invalid number, please,\nreboot the program and try again later.");
                        break;
                    }
            }
        }
        static string FromTwoToEight (string s)
        {
            string result = "";
            while (s.Length > 0)
            {
                string sub;
                if (s.Length / 3 > 0)
                {
                    sub = s.Substring(s.Length - 3);
                    s = s.Remove(s.Length - 3);
                }
                else
                {
                    sub = s;
                    if (s.Length == 1)
                        sub = "00" + s;
                    else
                        sub = "0" + s;
                    s = "";
                }
                switch (sub)
                {
                    case "000":
                        {
                            result = "0"+ result;
                            break;
                        }
                    case "001":
                        {
                            result = "1" + result;
                            break;
                        }
                    case "010":
                        {
                            result =  "2" + result;
                            break;
                        }
                    case "011":
                        {
                            result = "3" + result;
                            break;
                        }
                    case "100":
                        {
                            result = "4" + result;
                            break;
                        }
                    case "101":
                        {
                            result = "5" + result;
                            break;
                        }
                    case "110":
                        {
                            result = "6" + result;
                            break;
                        }
                    case "111":
                        {
                            result = "7" + result;
                            break;
                        }
                }
            }
            return result;
        }
        static string FromTwoToSixteen (string s)
        {
            string result = "";
            while (s.Length > 0)
            {
                string sub;
                if (s.Length / 4 > 0)
                {
                    sub = s.Substring(s.Length - 4);
                    s = s.Remove(s.Length - 4);
                }
                else
                {
                    sub = s;
                    if (s.Length == 1)
                        sub = "000" + s;
                    else if (s.Length == 2)
                        sub = "00" + s;
                    else
                        sub = "0" + s;
                    s = "";
                }
                switch (sub)
                {
                    case "0000":
                        {
                            result = "0" + result;
                            break;
                        }
                    case "0001":
                        {
                            result = "1" + result;
                            break;
                        }
                    case "0010":
                        {
                            result = "2" + result;
                            break;
                        }
                    case "0011":
                        {
                            result = "3" + result;
                            break;
                        }
                    case "0100":
                        {
                            result = "4" + result;
                            break;
                        }
                    case "0101":
                        {
                            result = "5" + result;
                            break;
                        }
                    case "0110":
                        {
                            result = "6" + result;
                            break;
                        }
                    case "0111":
                        {
                            result = "7" + result;
                            break;
                        }
                    case "1000":
                        {
                            result = "8" + result;
                            break;
                        }
                    case "1001":
                        {
                            result = "9" + result;
                            break;
                        }
                    case "1010":
                        {
                            result = "A" + result;
                            break;
                        }
                    case "1011":
                        {
                            result = "B" + result;
                            break;
                        }
                    case "1100":
                        {
                            result = "C" + result;
                            break;
                        }
                    case "1101":
                        {
                            result = "D" + result;
                            break;
                        }
                    case "1110":
                        {
                            result = "E" + result;
                            break;
                        }
                    case "1111":
                        {
                            result = "F" + result;
                            break;
                        }
                }
            }
            return result;
        }
        static double FromNToTen (string s,int n)  // FROM N TO 10
        {
            string result = "";
            double temp, sum = 0;
            double system = n;
            for (int i=0;i<s.Length;i++)         //1 variant
            {
                temp = Convert.ToInt32(s[s.Length-i-1])-48;
                temp= temp* Math.Pow(n, i);
                sum += temp;
            }
             /*for(int i=0;i<s.Length;i++)           //2 variant
            {
                if (s[s.Length-i-1]=='1')
                {
                    sum += Math.Pow(2, i);
                }
            }*/
            return sum;
        }
        static string FromTenToTwo (string s)
        {
            string result = "";
            int number = Convert.ToInt32(s);
            while(number>0)
            {
                if (number % 2 == 0)
                    result = "0"+ result;
                else
                    result = "1" + result;
                number = number / 2;
            }
            return result;
        }

    }
}