qwert

 private static void NewMethod3<U>()
        {
            Console.WriteLine("сколько создать экземпляров?");
            int number = 0;
            U[] test1;
            Int32.TryParse(Console.ReadLine(), out number);
            if (number == 0)
            {
                test1 = new U[1];

            }
            else
            {
                test1 = new U[number];

            }
            Console.WriteLine("использовать конструктор с параметрами?(true или false)");
            bool check;
            if (bool.TryParse(Console.ReadLine(), out check))
            {
                if (check == true)
                {
                    check = false;

                    for (int i = 0; i < test1.Length; i++)
                    {
                        test1[i] = new U (i, "this is task", "name", "At");
                    }
                }

                else
                {
                    for (int i = 0; i < test1.Length; i++)
                    {
                        test1[i] = new U();
                    }
                }
                //tempfun tempfun1;
                //for (int i = 0; i < test1.Length; i++)
                //{
                //    tempfun1 = test1[i].name;
                //}
            }


            else
            {
                Console.WriteLine("неправильный ввод");
            }
        }
// класс
class test : Interph, inter1
    {
        private int returnnumber;
        private string taskstring;
        private string namestring;
        private string groupstring;

        public int Returnnumber { get => returnnumber; set => returnnumber = value; }
        public string Taskstring { get => taskstring; set => taskstring = value; }
        public string Namestring { get => namestring; set => namestring = value; }
        public string Groupstring { get => groupstring; set => groupstring = value; }

        public test(int number, string task, string name, string group)
        {
            Returnnumber = number;
            Namestring = name;
            Taskstring = task;
            Groupstring = group;

        }
        public test()
        {
            Returnnumber = 8;
            Taskstring = "default";
            Namestring = "default";
            Groupstring = "default";
        }