using System;

public class Program

{

    public static void Main()

    {   

        bool endApp = false;

        Console.WriteLine("-----------------------CALCULATOR--------------------");

        while(!endApp){

            string numInput1 = "";

            string numInput2 = "";

            double result = 0;

        Console.WriteLine("Introduceti un numar");

            numInput1 = Console.ReadLine();

            double cleanNum1 = 0;

            while(!double.TryParse(numInput1, out cleanNum1)){

        Console.WriteLine("A fost introdus un numar invalid, introduceti din nou");

        numInput1 = Console.ReadLine();

        }

                Console.WriteLine("Introduceti un numar");

            numInput2 = Console.ReadLine();

            double cleanNum2 = 0;

            while(!double.TryParse(numInput2, out cleanNum2)){

        Console.WriteLine("A fost introdus un numar invalid, introduceti din nou");

        numInput2 = Console.ReadLine();

        }

            Console.WriteLine("Alegeti optiunea:");

            Console.WriteLine("\ta - adunare");

            Console.WriteLine("\tb - scadere");

            Console.WriteLine("\tc - inmultire");

            Console.WriteLine("\td - impartire");

            string option = Console.ReadLine();

        try{

            result  = Calculator.DoOperation(cleanNum1, cleanNum2, option);

            if(double.IsNaN(result)){

                Console.WriteLine("Eroare matematica");

            }

            else

                Console.WriteLine("Your result {0:0.##}\n", result);

        }catch(Exception e){

        Console.WriteLine("A aparut o eroare: " + e.Message);

        }

            Console.WriteLine("-------------------------");

            Console.WriteLine("Pentru a inchide programa tastati 'n'");

            Console.WriteLine("Tastati orice buton pentru a continua");

            if(Console.ReadLine() == "n") endApp = true;

    }

}

public class Calculator{

    public static double DoOperation(double num1, double num2, string option){

        double result = double.NaN;

        switch(option){

            case "a":

                result = num1 + num2;

                break;

            case "b":

                result = num1 - num2;

                break;

            case "c":

                result = num1 * num2;

                break;

            case "d":

                result = num1 / num2;

                break;  

            default:

                break;

        }

        return result;

    }

}

}

​

​