Choice / 359str/11

using System;

namespace Caaaa
{
    class Program
    {
        static int Rev(int k) //method 1
        {
            int k1 = 0;
            while (k!=0)
            {
                k1 = k1 * 10 + k % 10;
                k = k / 10;
            }
            return k1;

        }
        static void Avg()  //2
        {
            Console.Write("br = ");
            int br = int.Parse(Console.ReadLine());
            int sum = 0;
            int x;
            for (int i = 0; i < br; i++)
            {
                Console.Write("x -> ");
                x = int.Parse(Console.ReadLine());
                sum = sum + x;

            }
            Console.WriteLine("avg = " + Math.Round(1.0 * sum / br,2));
        }

        static double Eq() //3
        {
            Console.Write("a = "); double a = double.Parse(Console.ReadLine());
            while (a == 0)
            {
             Console.Write("a = ");  a = double.Parse(Console.ReadLine());
            }
            Console.Write("b = "); double b = double.Parse(Console.ReadLine());
            return Math.Round(-b / a,2);
        }
        static void Main(string[] args)
        {
            int ch;
            int K;
            double x;
            do
            {
                Console.WriteLine("1 - reverse ");
                Console.WriteLine("2 - avg ");
                Console.WriteLine("3 - eq ");
                Console.WriteLine("4 - finish ");
                Console.Write("your choice : ");
                ch = int.Parse(Console.ReadLine());
                switch (ch)
                {
                    case 1: Console.Write("K = "); K = int.Parse(Console.ReadLine());
                        Console.WriteLine(" k1 = " + Rev(K)); break;
                    case 2: Avg(); break;
                    case 3: x = Eq(); Console.WriteLine("x = " + x); break;

                }
            } while (ch!=4);
        }
    }
}