using System;

namespace application{

public class myCalculator

{

    public static void Main()

    {

        while(true){

        Console.WriteLine("\n Calculator \n Enter the first number:");

        int a = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Enter second number");

        int b = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("choose operation\n 1.product\n 2.Subtract\n 3.Addition\n 4.Division");

        int c = Convert.ToInt32(Console.ReadLine());

        switch (c){

            case 1: String d= Convert.ToString(a*b);

                Console.WriteLine("Product:"+ d);

                break;

            case 2: if(a>b) Console.WriteLine("Difference:"+ Convert.ToString(a-b));

                else    Console.WriteLine("Difference:"+ Convert.ToString(b-a));

                break;

            case 3: Console.WriteLine("Sum:"+ Convert.ToString(a-b));

                break;

            case 4:Console.WriteLine("Division:"+ Convert.ToString(a/b));

                break;

            default :Console.WriteLine("Enter valid option");

                break;

          double x,z,a;

            Console.WriteLine("X=");

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

            Console.WriteLine("a=");

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

​

            if (x>2)

            {

                z = Math.Log(Math.Pow(x, 2)) / Math.Log(3) + Math.Sqrt(Math.Pow(x,3));

            } else

                if (x==2) 

            {

                z = Math.Sqrt(x * x + 16) - Math.Exp(2*x);

            }

            else

            {

                z = Math.Pow(a, x) + Math.Abs(x * x * x);  

            }

​

            Console.WriteLine("Natija z=" + z);

        }

        }

        }

    }

}