using System;

​

public class Program

{

        public static void COMPUTE()

        {

            Console.WriteLine("\n\nChoose what action will be executed:");

            Console.WriteLine("\n1 = To compute the area of the circle");

            Console.WriteLine("2 = To compute the volume of a cube");

            Console.WriteLine("3 = To compute the perimeter if a triangle");

            Console.WriteLine("4 = To compute the surface area of a rectangle");

            Console.WriteLine("5 = To exit the program");

        }

        public static void Main()

        {

            int action = 0;

​

            while (action != 5)

            {

                COMPUTE();

                Console.Write("\nEnter number to execute action: ");

                int.TryParse(Console.ReadLine(), out action);

​

                if (action == 5)

                    break;

​

                while (action < 1 || action > 5)

                {

                    Console.WriteLine("\nERROR\nINCORRECT NUMBER");

                    COMPUTE();

                    Console.Write("\nEnter number to execute action: ");

                    int.TryParse(Console.ReadLine(), out action);

                }

​

                if (action == 1)

                    AreaCircle();

                else if (action == 2)

                    VolumeCube();

                else if (action == 3)

                    PerimeterTriangle();

                else if (action == 4)

                    SurfaceAreaRec();

            }

        }

​

        public static void AreaCircle()

        {

            double area;

        double rad;

        Console.WriteLine("Enter the radius of the circle:");

            rad=Convert.ToDouble(Console.ReadLine());

        area=3.14*rad*rad;

        Console.WriteLine("\nThe area of the circle is {0}", area);

        }

​

        public static void VolumeCube()

        {

            int VolCube;

        Console.WriteLine("Enter the desired lenght of the cube's edge: ");

            int a=int.Parse(Console.ReadLine());

        VolCube=a*a*a;

        Console.WriteLine("The volume of the cube is "+ VolCube);

        }

​

        public static void PerimeterTriangle()

        {

            int PerimTri;

        Console.WriteLine("Enter a:");

            int a=int.Parse(Console.ReadLine());

        Console.WriteLine("Enter b:");

            int b=int.Parse(Console.ReadLine());

        Console.WriteLine("Enter c:");

            int c=int.Parse(Console.ReadLine());

        PerimTri=a+b+c;

        Console.WriteLine("The perimeter of the Triangle is "+ PerimTri);

        }

​

        public static void SurfaceAreaRec()

        {   

        int SurfArea;

        Console.WriteLine("Enter the lenght of the rectangular prism: ");

            int a=int.Parse(Console.ReadLine());

        Console.WriteLine("Enter the height of the rectangular prism: ");

            int b=int.Parse(Console.ReadLine());

        Console.WriteLine("Enter the width of the rectangular prism: ");

            int c=int.Parse(Console.ReadLine());

        SurfArea=2*a*b+2*b*c+2*c*a;

        Console.WriteLine("\n\nThe surface area of the rectangular prism is "+ SurfArea+" units");

        }

}