using System;

public class Calculator

{

    public static void Main()

    {

        double pi = Math.PI;

        Console.WriteLine("Select 1 for area of a circle\nSelect 2 for standard calculations");

        int num = Convert.ToInt16(Console.ReadLine());

        if (num == 1)

        {

            Console.WriteLine("Enter the radius in cm");

            double num4 = Convert.ToDouble(Console.ReadLine());

            double pinum = pi * num4 * num4;

            double num5 = pinum / pi;

            Console.WriteLine("The area is " + pinum + "cm² (" + num5 + "π)");

        }

        else if (num == 2)

        {

        Console.WriteLine("Enter the first number");

        double num1 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Enter the second number");

        double num2 = Convert.ToDouble(Console.ReadLine());

        Console.WriteLine("Select Between + - * /");

        string cal = (Console.ReadLine());

        if (cal == "*")

        {

            double num3 = num1 * num2;

            Console.WriteLine("Final number is " + num3);

        }

        else if(cal == "+")

        {

            double num3 = num1 + num2;

            Console.WriteLine("Final number is " + num3);

        }

        else if(cal == "-")

        {

            double num3 = num1 - num2;

            Console.WriteLine("Final number is " + num3);

        }

        else if(cal == "/")

        {

            double num3 = num1 / num2;

            Console.WriteLine("Final number is " + num3);

        }

        }

    }

}