using System;

public class Program

{

    public static void Main()

    {

        string inputShape;

        byte shape;         Console.WriteLine("Enter 1 for a rectangle; enter 2 for a triangle; enter 3 for a circle");

        inputShape = Console.ReadLine();

        bool parseSuccess = byte.TryParse(inputShape, out shape);

        while (parseSuccess == false)

        {

            Console.WriteLine("You entered an invalid number.");

            Console.WriteLine("Enter 1 for a square; enter 2 for a triangle; enter 3 for a circle");

            inputShape = Console.ReadLine();

            parseSuccess = byte.TryParse(inputShape, out shape);

        }

        if (shape == 1)

        {

            Console.WriteLine("Please enter the length and width of your rectangle");

            Console.Write("Length: ");

            string inputLength = Console.ReadLine();

            double length;

            while (double.TryParse(inputLength, out length) == false)

            {

                Console.Write("Please enter a valid length of your rectangle: ");

                inputLength = Console.ReadLine();

            }

            Console.Write("Width: ");

            string inputWidth = Console.ReadLine();

            double width;

            while (double.TryParse(inputWidth, out width) == false)

            {

                Console.Write("Please enter a valid width of your rectangle: ");

                inputWidth = Console.ReadLine();

            }

            decimal area = (decimal)(length*width);

            decimal perimeter = (decimal)((2* length) + (2 * width));

            Console.WriteLine("The area of your rectangle is: {0} unit(s)^2. The perimeter of your rectangle is: {1} unit(s).", area, perimeter);

        }

        if (shape == 2)

        {

            Console.WriteLine("Please enter the base and hight of your triangle");

            Console.Write("Base: ");

            string inputBase = Console.ReadLine();

            double triBase;

            double triHight;

            while (double.TryParse(inputBase, out triBase) == false)

            {

                Console.Write("Please enter a valid base of your triangle: ");

                inputBase = Console.ReadLine();

            }

            Console.Write("Hight: ");

            string inputHight = Console.ReadLine();

            while (double.TryParse(inputHight, out triHight) == false)

            {

                Console.Write("Please enter a valid hight of your triangle: ");

                inputHight = Console.ReadLine();

            }

            decimal area = (decimal)(0.5d * triBase * triHight);

            Console.WriteLine("The area of your triangle is: {0} unit(s)^2", area);

        }

        if (shape == 3)

        {

            string inputRadius;

            double radius;

            decimal circumference;

            decimal area;

            double pi = Math.PI;

            Console.Write("Please enter the radius of your circle: ");

            inputRadius = Console.ReadLine();

            while (double.TryParse(inputRadius, out radius) == false)

            {

                Console.Write("Please enter a valid radius of your circle: ");

                inputRadius = Console.ReadLine();

            }

            area = (decimal)(pi * radius * radius);

            circumference = (decimal)(2.0 * pi * radius);

            Console.WriteLine("The area of your circle is: {0} units^2. The circumference of your circle is: {1}.", area, circumference);

        }

    }

}