using System;

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Nhap so he co so [16]:");

        string Hexa = Console.ReadLine();

​

        string Binario = ChuyenDoi(Hexa);

        Console.WriteLine("Ket qua chuyen doi [2] la: " + Binario);

    }

​

    public static string ChuyenDoi(string Hexa)

    {

        string Binario = "";

        int Decimal = 0;

        int m = 0;

​

        for (int i = Hexa.Length - 1; i >= 0; i--)

        {

            int vt;

            char kt = Hexa[i];

​

            if (char.IsDigit(kt))

            {

                vt = int.Parse(Hexa[i].ToString());

            }

            else

            {

                switch (kt)

                {

                    case 'A':

                        vt = 10;

                        break;

                    case 'B':

                        vt = 11;

                        break;

                    case 'C':

                        vt = 12;

                        break;

                    case 'D':

                        vt = 13;

                        break;

                    case 'E':

                        vt = 14;

                        break;

                    case 'F':

                        vt = 15;

                        break;

                    default:

                        throw new ArgumentException("Khong hop le!");

                }

            }

​

            Decimal += vt * (int)Math.Pow(16, m);

            m++;

        }

​

        while (Decimal > 0)

        {

            int sodu = Decimal % 2;

            Binario = sodu + Binario;

            Decimal /= 2;

        }

​

        return Binario;

    }

}