using System;

​

namespace ConsoleApp

{

    class Program

    {

        static void Main(string[] args)

        {

            Menu();

        }

​

        static char ReadLowerChar()

        {

            return char.ToLower(Console.ReadLine()[0]);

        }

        static double ReadDouble(string msg)

        {

            Console.Write(msg);

            return double.Parse(Console.ReadLine());

        }

​

        static void Menu()

        {

            while (true)

            {

                Console.WriteLine();

                Console.WriteLine("Main menu:");

                Console.WriteLine("A. Area");

                Console.WriteLine("P. Perimeter");

                Console.WriteLine("V. Volume");

                Console.WriteLine("X. Exit");

                Console.Write("Choose: ");

                char input = ReadLowerChar();

​

                switch (input)

                {

                    case 'a':

                        AreaMenu();

                        break;

                    case 'p':

                        PerimiterMenu();

                        break;

                    case 'v':

                        VolumeMenu();

                        break;

                    case 'x':

                        Console.WriteLine("Exited");

                        return;

                    default:

                        Console.WriteLine("Invalid input " + input);

                        break;

                }

            }

        }

​

        static void AreaMenu()

        {

            while (true)

            {

                Console.WriteLine();

                Console.WriteLine("Area menu:");

                Console.WriteLine("C. Circle");

                Console.WriteLine("E. Eclipse");

                Console.WriteLine("T. Trapezoid");

                Console.WriteLine("M. Main Menu");

                Console.Write("Choose: ");

                char input = ReadLowerChar();

                double area, a, b, h, radius;

​

                switch (input)

                {

                    case 'c':

                        radius = ReadDouble("Enter radius: ");

                        area = ComputeCircleArea(radius);

                        Console.WriteLine($"Circle Area: {area}");

                        break;

                    case 'e':

                        a = ReadDouble("Enter side a: ");

                        b = ReadDouble("Enter side b: ");

                        area = ComputeEclipseArea(a, b);

                        Console.WriteLine($"Eclipse Area: {area}");

                        break;

                    case 't':

                        a = ReadDouble("Enter side a: ");

                        b = ReadDouble("Enter side b: ");

                        h = ReadDouble("Enter height: ");

                        area = ComputeTrapezoidArea(a, b, h);

                        Console.WriteLine($"Trapezoid Area: {area}");

                        break;

                    case 'm':

                        Console.WriteLine("Returned to Main Menu");

                        return;

                    default:

                        Console.WriteLine("Invalid input " + input);

                        break;

                }

            }

        }

​

        static void PerimiterMenu()

        {

            while (true)

            {

                Console.WriteLine();

                Console.WriteLine("Perimiter menu:");

                Console.WriteLine("C. Circle");

                Console.WriteLine("E. Equilateral Triangle");

                Console.WriteLine("T. Trapezoid");

                Console.WriteLine("M. Main Menu");

                Console.Write("Choose: ");

                char input = ReadLowerChar();

                double perimeter, a, b, c, d, radius;

​

                switch (input)

                {

                    case 'c':

                        radius = ReadDouble("Enter radius: ");

                        perimeter = ComputeCirclePerimiter(radius);

                        Console.WriteLine($"Circle Perimiter: {perimeter}");

                        break;

                    case 'e':

                        a = ReadDouble("Enter side: ");

                        perimeter = ComputeEquilateralTrianglePerimiter(a);

                        Console.WriteLine($"Equilateral Triangle Perimiter: {perimeter}");

                        break;

                    case 't':

                        a = ReadDouble("Enter side a: ");

                        b = ReadDouble("Enter side b: ");

                        c = ReadDouble("Enter side c: ");

                        d = ReadDouble("Enter side d: ");

                        perimeter = ComputeTrapezoidPerimiter(a, b, c, d);

                        Console.WriteLine($"Trapezoid Perimeter: {perimeter}");

                        break;

                    case 'm':

                        Console.WriteLine("Returned to Main Menu");

                        return;

                    default:

                        Console.WriteLine("Invalid input " + input);

                        break;

                }

            }

        }

​

        static void VolumeMenu()

        {

            while (true)

            {

                Console.WriteLine();

                Console.WriteLine("Volume menu:");

                Console.WriteLine("C. Cube");

                Console.WriteLine("R. Right Circular Cone");

                Console.WriteLine("S. Sphere");

                Console.WriteLine("M. Main Menu");

                Console.Write("Choose: ");

                char input = ReadLowerChar();

                double volume, a, radius, height;

​

                switch (input)

                {

                    case 'c':

                        a = ReadDouble("Enter side: ");

                        volume = ComputeCubeVolume(a);

                        Console.WriteLine($"Cube Volume: {volume}");

                        break;

                    case 'r':

                        radius = ReadDouble("Enter radius: ");

                        height = ReadDouble("Enter height: ");

                        volume = ComputeRightCircularConeVolume(radius, height);

                        Console.WriteLine($"Right Circular Cone Volume: {volume}");

                        break;

                    case 's':

                        radius = ReadDouble("Enter radius: ");

                        volume = ComputeSphereVolume(radius);

                        Console.WriteLine($"Sphere Volume: {volume}");

                        break;

                    case 'm':

                        Console.WriteLine("Returned to Main Menu");

                        return;

                    default:

                        Console.WriteLine("Invalid input " + input);

                        break;

                }

            }

        }

​

        static double ComputeCircleArea(double radius)

        {

            return Math.PI * Math.Pow(radius, 2);

        }

        static double ComputeEclipseArea(double a, double b)

        {

            return Math.PI * a * b;

        }

        static double ComputeTrapezoidArea(double a, double b, double h)

        {

            return (a + b) / 2 * h;

        }

​

        static double ComputeCirclePerimiter(double radius)

        {

            return 2 * Math.PI * radius;

        }

        static double ComputeEquilateralTrianglePerimiter(double side)

        {

            return 3 * side;

        }

        static double ComputeTrapezoidPerimiter(double a, double b, double c, double d)

        {

            return a + b + c + d;

        }

        static double ComputeCubeVolume(double side)

        {

            return Math.Pow(side, 3);

        }

        static double ComputeRightCircularConeVolume(double radius, double height)

        {

            return (1 / 3) * Math.PI * Math.Pow(radius, 2) * height;

        }

        static double ComputeSphereVolume(double radius)

        {

            return 4 * Math.PI * Math.Pow(radius, 3);

        }

    }

}