static class Methods
    {
        public static double Fun1() => Math.PI;
        public static double Fun2() => Math.E;
        public static double Fun3() => Math.Tau;
        public static double Fun4() => 273.15;
        public static double Fun5() => 1;
        public static double Fun6() => 2300;
        public static double Fun7() => 0.1;
        public static double Fun8() => 100;
        public static double Fun9() => 1987;
        public static double Fun10() => 450;
    }



    interface IInterface
    {
        public static IInterface Get_random_implementation()
        {
            int random_index = Random.Shared.Next(0, 10);

            switch (random_index)
            {
                case 0: return new Impl1();
                case 1: return new Impl2();
                case 2: return new Impl3();
                case 3: return new Impl4();
                case 4: return new Impl5();
                case 5: return new Impl6();
                case 6: return new Impl7();
                case 7: return new Impl8();
                case 8: return new Impl9();
                case 9: return new Impl10();
                default: throw new Exception();
            }
        }

        double Get_value();
    }


    class Impl1 : IInterface { public double Get_value() => Methods.Fun1(); }

    class Impl2 : IInterface { public double Get_value() => Methods.Fun2(); }

    class Impl3 : IInterface { public double Get_value() => Methods.Fun3(); }

    class Impl4 : IInterface { public double Get_value() => Methods.Fun4(); }

    class Impl5 : IInterface { public double Get_value() => Methods.Fun5(); }

    class Impl6 : IInterface { public double Get_value() => Methods.Fun6(); }

    class Impl7 : IInterface { public double Get_value() => Methods.Fun7(); }

    class Impl8 : IInterface { public double Get_value() => Methods.Fun8(); }

    class Impl9 : IInterface { public double Get_value() => Methods.Fun9(); }

    class Impl10 : IInterface { public double Get_value() => Methods.Fun10(); }




    public class Tester
    {
        public static void Run()
        {
            Run_with_BenchmarkDotNet();
            //Run_with_manual_swopwatch();
        }

        public static void Run_with_BenchmarkDotNet()
        {
            BenchmarkDotNet.Reports.Summary? summary = BenchmarkRunner.Run<Tester>();
        }


        //public static void Run_with_manual_swopwatch()
        //{
        //    Stopwatch sw = new();
        //    Tester tester = new();


        //    int nit = 50;

        //    Call("Test_interface", tester.Test_interface, nit);
        //    Call("Test_multiple_ifs", tester.Test_multiple_ifs, nit);
        //    Call("Test_swith", tester.Test_swith, nit);
        //    Call("Test_arr", tester.Test_arr, nit);
        //    Call("Test_delegate_array", tester.Test_delegate_array, nit);
        //}


        //static void Call(string name, Func<double> method, int nit)
        //{
        //    Stopwatch sw = new();
        //    sw.Start();
        //    double sum = 0;
        //    for (int i = 0; i < nit; i++)
        //    {
        //        sum = method();
        //    }
        //    sw.Stop();
        //    double dur = sw.Elapsed.TotalMilliseconds / nit;
        //    Console.WriteLine($"{name}. Sum = {sum:N0}. Time per oper = {dur:N1} ms");
        //}




        const int m = 10_000;
        int[] random_indexes = new int[m];
        IInterface[] interface_implementations = new IInterface[m];
        double[] values = new double[m];
        Func<double>[] delegates = new Func<double>[m];


        public Tester()
        {
            for (int i = 0; i < m; i++)
            {
                random_indexes[i] = Random.Shared.Next(0, 10);
                interface_implementations[i] = IInterface.Get_random_implementation();
                values[i] = Get_value(Random.Shared.Next(0, 10));
                delegates[i] = Get_delegate(Random.Shared.Next(0, 10));
            }
        }


        public double Get_value(int random_index)
        {
            if (random_index == 0) return Methods.Fun1();
            else if (random_index == 1) return Methods.Fun2();
            else if (random_index == 2) return Methods.Fun3();
            else if (random_index == 3) return Methods.Fun4();
            else if (random_index == 4) return Methods.Fun5();
            else if (random_index == 5) return Methods.Fun6();
            else if (random_index == 6) return Methods.Fun7();
            else if (random_index == 7) return Methods.Fun8();
            else if (random_index == 8) return Methods.Fun9();
            else if (random_index == 9) return Methods.Fun10();
            else throw new Exception();
        }

        public Func<double> Get_delegate(int random_index)
        {
            if (random_index == 0) return Methods.Fun1;
            else if (random_index == 1) return Methods.Fun2;
            else if (random_index == 2) return Methods.Fun3;
            else if (random_index == 3) return Methods.Fun4;
            else if (random_index == 4) return Methods.Fun5;
            else if (random_index == 5) return Methods.Fun6;
            else if (random_index == 6) return Methods.Fun7;
            else if (random_index == 7) return Methods.Fun8;
            else if (random_index == 8) return Methods.Fun9;
            else if (random_index == 9) return Methods.Fun10;
            else throw new Exception();
        }


        [Benchmark]
        public double Test_interface()
        {
            double sum = 0;
            for (int i = 0; i < m; i++)
            {
                sum += interface_implementations[i].Get_value();
            }

            return sum;
        }


        [Benchmark]
        public double Test_multiple_ifs()
        {
            double sum = 0;
            for (int i = 0; i < m; i++)
            {
                int random_index = random_indexes[i];
                if (random_index == 0) sum += Methods.Fun1();
                else if (random_index == 1) sum += Methods.Fun2();
                else if (random_index == 2) sum += Methods.Fun3();
                else if (random_index == 3) sum += Methods.Fun4();
                else if (random_index == 4) sum += Methods.Fun5();
                else if (random_index == 5) sum += Methods.Fun6();
                else if (random_index == 6) sum += Methods.Fun7();
                else if (random_index == 7) sum += Methods.Fun8();
                else if (random_index == 8) sum += Methods.Fun9();
                else if (random_index == 9) sum += Methods.Fun10();
                else throw new Exception();
            }

            return sum;
        }



        [Benchmark]
        public double Test_swith()
        {
            double sum = 0;
            for (int i = 0; i < m; i++)
            {
                switch (random_indexes[i])
                {
                    case 0: sum += Methods.Fun1(); break;
                    case 1: sum += Methods.Fun2(); break;
                    case 2: sum += Methods.Fun3(); break;
                    case 3: sum += Methods.Fun4(); break;
                    case 4: sum += Methods.Fun5(); break;
                    case 5: sum += Methods.Fun6(); break;
                    case 6: sum += Methods.Fun7(); break;
                    case 7: sum += Methods.Fun8(); break;
                    case 8: sum += Methods.Fun9(); break;
                    case 9: sum += Methods.Fun10(); break;
                    default: throw new Exception();
                }
            }

            return sum;
        }


        [Benchmark]
        public double Test_arr()
        {
            double sum = 0;
            for (int i = 0; i < m; i++)
            {
                sum += values[i];
            }

            return sum;
        }


        [Benchmark]
        public double Test_delegate_array()
        {
            double sum = 0;
            for (int i = 0; i < m; i++)
            {
                sum += delegates[i]();
            }

            return sum;
        }
    }