Additional Input methods

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _7.SToD
{
    class SToD
    {
        static void Main(string[] args)
        {
            Console.Write("Enter s=?\b");
            int s = int.Parse(Console.ReadLine());
            Console.Write("Enter d=?\b");
            int d = int.Parse(Console.ReadLine());
            if (s==2 && d == 10)
            {
                BinToDec();
            }
            else if (s == 2 && d == 16)
            {
                BinToHex();
            }
            else if (s == 10 && d == 2)
            {
                DecToBin();
            }
            else if (s == 10 && d == 16)
            {
                DecToHex();
            }
            else if (s==16 && d == 10)
            {
                HexToDec();
            }
            else if(s == 16 && d == 2)
            {
                HexToBin();
            }
        }

        private static void BinToDec()
        {
            string binNumber = InputNumberAsString();

            double dec = new int();
            char[] bin = binNumber.ToCharArray();
            for (int i = bin.Length - 1; i >= 0; i--)
            {
                if (bin[i] != '0')
                {
                    dec += Math.Pow(2, i);
                }
            }
            Console.WriteLine(dec);
        }

        //Първия метод за методите,в които се въвежда число в 16-на бройна система
        private static string InputNumberAsString()
        {
            Console.Write("Enter number to convert:");
            string number = Console.ReadLine();
            return number;
        }

        private static void BinToHex()
        {
            //Въвеждането е изкарано в отделен метод. Така няма нужда да преписваш един и
            //същи код постоянно.
            string binNumber = InputNumberAsString();
            string result = "";

            for (int i = 0; i < binNumber.Length; i += 4)
            {
                switch (binNumber.Substring(i, 4))
                {
                    case "0000":
                        result += "0";
                        break;
                    case "0001":
                        result += "1";
                        break;
                    case "0010":
                        result += "2";
                        break;
                    case "0011":
                        result += "3";
                        break;
                    case "0100":
                        result += "4";
                        break;
                    case "0101":
                        result += "5";
                        break;
                    case "0110":
                        result += "6";
                        break;
                    case "0111":
                        result += "";
                        break;
                    case "1000":
                        result += "8";
                        break;
                    case "1001":
                        result += "9";
                        break;
                    case "1010":
                        result += "A";
                        break;
                    case "1011":
                        result += "B";
                        break;
                    case "1100":
                        result += "C";
                        break;
                    case "1101":
                        result += "D";
                        break;
                    case "1110":
                        result += "E";
                        break;
                    case "1111":
                        result += "F";
                        break;
                    default:
                        result += "";
                        break;
                }
            }
            Console.WriteLine(result);
        }

        private static void DecToBin()
        {
            //Това е вторият метод, но може и само един метод а " парсването да извършваш тук"
            int num = InputNumber();
            StringBuilder result = new StringBuilder();
            int counter = 0;
            int testNum = num;
            while (testNum != 0)
            {
                testNum = testNum >> counter;
                counter++;
            }
            while (counter >= 0)
            {

                result.Append((num & (1 << counter)) >> counter);
                counter--;
            }
            result.Remove(0, 1);
            Console.WriteLine(result);
        }

        private static void DecToHex()
        {
            int num = InputNumber();
            StringBuilder hexNum = new StringBuilder();
            while (num > 1)
            {
                int temp = num % 16;
                if (temp > 9)
                {
                    switch (temp)
                    {
                        case 10:
                            hexNum.Append('A');
                            break;
                        case 11:
                            hexNum.Append('B');
                            break;
                        case 12:
                            hexNum.Append('C');
                            break;
                        case 13:
                            hexNum.Append('D');
                            break;
                        case 14:
                            hexNum.Append('E');
                            break;
                        case 15:
                            hexNum.Append('F');
                            break;
                    }
                }
                else
                {
                    hexNum.Append(temp);
                }
                num /= 16;
            }
            for (int i = hexNum.Length - 1; i >= 0; i--)
            {
                Console.Write(hexNum[i]);
            }
        }

        //Втория метод - са число в 10-на бройна система
        private static int InputNumber()
        {
            Console.Write("Enter number to convert:");
            int num = int.Parse(Console.ReadLine());
            return num;
        }

        private static void HexToDec()
        {
            string hexNumber = InputNumberAsString();
            int power = hexNumber.Length - 1;
            int digit = 0;
            double result = 0;

            for (int i = 0; i < hexNumber.Length; i++)
            {
                switch (hexNumber[i])
                {
                    case 'A':
                        digit = 10;
                        break;
                    case 'B':
                        digit = 11;
                        break;
                    case 'C':
                        digit = 12;
                        break;
                    case 'D':
                        digit = 13;
                        break;
                    case 'E':
                        digit = 14;
                        break;
                    case 'F':
                        digit = 15;
                        break;
                    default:
                        digit = int.Parse(hexNumber[i].ToString());
                        break;
                }
                result += digit * Math.Pow(16, power);
                power--;
            }

            Console.WriteLine(result);
        }

        private static void HexToBin()
        {
            string hexNumber = InputNumberAsString();
            string result = "";
            for (int i = 0; i < hexNumber.Length; i++)
            {
                switch (hexNumber.Substring(i, 1))
                {
                    case "0":
                        result += "0000";
                        break;
                    case "1":
                        result += "0001";
                        break;
                    case "2":
                        result += "0010";
                        break;
                    case "3":
                        result += "0011";
                        break;
                    case "4":
                        result += "0100";
                        break;
                    case "5":
                        result += "0101";
                        break;
                    case "6":
                        result += "0110";
                        break;
                    case "7":
                        result += "0111";
                        break;
                    case "8":
                        result += "1000";
                        break;
                    case "9":
                        result += "1001";
                        break;
                    case "A":
                        result += "1010";
                        break;
                    case "B":
                        result += "1011";
                        break;
                    case "C":
                        result += "1100";
                        break;
                    case "D":
                        result += "1101";
                        break;
                    case "E":
                        result += "1110";
                        break;
                    case "F":
                        result += "1111";
                        break;
                    default:
                        result += "";
                        break;
                }
            }
            Console.WriteLine(result.TrimStart(' ', '0'));
        }
    }
}