class Program
    {
        static void Main(string[] args)
        {
            int arrayLengthOne = 6;
            int arrayLengthTwo = 4;

            string[] arrayNumberOne = new string[arrayLengthOne];
            string[] arrayNumberTwo = new string[arrayLengthTwo];

            FillNumbers(arrayNumberOne);
            FillNumbers(arrayNumberTwo);

            Print(arrayNumberOne);
            Print(arrayNumberTwo);

            List<string> uniqueNumbers = new List<string>();

            JoinArray(uniqueNumbers, arrayNumberOne);
            JoinArray(uniqueNumbers, arrayNumberTwo);

            Console.WriteLine(string.Join(" ", uniqueNumbers));

            Console.ReadKey();
        }

        private static void FillNumbers(string[] array, int maxNumber = 6, int minNumber = 0)
        {
            Random random = new Random(DateTime.Now.Millisecond);
            int randomNumber;

            for (int i = 0; i < array.Length; i++)
            {
                randomNumber = random.Next(minNumber, maxNumber + 1);
                array[i] = randomNumber.ToString();
            }
        }

        private static void Print(string[] arrayNumber)
        {
            Console.WriteLine(String.Join(" ", arrayNumber));
        }

        private static void JoinArray(List<string> uniqueNumbers, string[] array)
        {
            for (int i = 0; i < array.Length; i++)
            {
                if (uniqueNumbers.Contains(array[i]) ==  false)
                    uniqueNumbers.Add(array[i]);
            }
        }
    }