2017-03-31_23-37-10.txt

static void Main(string[] args)
{
    int num = int.Parse(Console.ReadLine());
    Console.WriteLine(deciToBinary(num));

    Console.ReadKey();
}
public static int deciToBinary(int num, int multiplier = 1)
{
    if (num == 0)
    {
        return 0;
    }
    else
    {
        //recursion
        return deciToBinary(num / 2, multiplier * 10) + (num % 2) * multiplier;
    }
}