HexadecimalToBinary

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

namespace _5.HexadecimalToBinary
{
    /*Write a program to convert hexadecimal numbers to binary numbers (directly).*/
    class Program
    {
        static void HexadecimalToBinary(string hex)
        {
            string binary = "";
            for (int i = 0; i < hex.Length; i++)
            {
                switch (hex[i])
                {
                    case '0': binary += " 0000"; break;
                    case '1': binary += " 0001"; break;
                    case '2': binary += " 0010"; break;
                    case '3': binary += " 0011"; break;
                    case '4': binary += " 0100"; break;
                    case '5': binary += " 0101"; break;
                    case '6': binary += " 0110"; break;
                    case '7': binary += " 0111"; break;
                    case '8': binary += " 1000"; break;
                    case '9': binary += " 1001"; break;
                    case 'A': binary += " 1010"; break;
                    case 'B': binary += " 1011"; break;
                    case 'C': binary += " 1100"; break;
                    case 'D': binary += " 1101"; break;
                    case 'E': binary += " 1110"; break;
                    case 'F': binary += " 1111"; break;
                    default: binary += ""; break;
                }
            }
            Console.WriteLine(binary);
        }
        static void Main(string[] args)
        {
            string hex = Console.ReadLine();
            HexadecimalToBinary(hex);
        }
    }
}