DEC->BIN

using System;

namespace Loops
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter DEC: ");
            int num = int.Parse(Console.ReadLine());
            int num1 = num;
            string bin = "";
            while (num != 0)
            {
                int rem = num % 2;
                bin += rem;
                num /= 2;
            }
            // reverse
            Console.Write($"{num1}(10) = ");
            for (int i = bin.Length - 1; i >= 0 ; i--)
            {
                Console.Write(bin[i]);
            }
            Console.WriteLine("(2)");
        }
    }
}