using System;

namespace CSLight
{
    public class Program
    {
        static void Main(string[] args)
        {
            const string OutputTextCommand = "1";
            const string OutputRandomNumberCommand = "2";
            const string ClearTextCommand = "3";
            const string ExitProgramCommand = "4";

            Random rnd = new Random();
            bool isWorking = true;

            while (isWorking)
            {
                Console.WriteLine($"{OutputTextCommand})Вывести текст.\n{OutputRandomNumberCommand})Сгерерировать число.\n{ClearTextCommand})Очистить консоль.\n{ExitProgramCommand})Выйти из программы.");

                switch (Console.ReadLine())
                {
                    case OutputTextCommand:
                        Console.WriteLine("Hello World!");
                        break;

                    case OutputRandomNumberCommand:
                        int number = rnd.Next(10);
                        break;

                    case ClearTextCommand:
                        Console.Clear();
                        break;

                    case ExitProgramCommand:
                        isWorking = false;
                    break;
                }
            }
        }
    }
}