using System;

​

public abstract class Calculator

{

    public abstract double Calculate(double num1, double num2);

}

​

public class AdditionCalculator : Calculator

{

    public override double Calculate(double num1, double num2)

    {

        return num1 + num2;

    }

}

​

public class SubtractionCalculator : Calculator

{

    public override double Calculate(double num1, double num2)

    {

        return num1 - num2;

    }

}

​

public class MultiplicationCalculator : Calculator

{

    public override double Calculate(double num1, double num2)

    {

        return num1 * num2;

    }

}

​

public class DivisionCalculator : Calculator

{

    public override double Calculate(double num1, double num2)

    {

        if (num2 == 0)

        {

            throw new DivideByZeroException("Cannot divide by zero.");

        }

        return num1 / num2;

    }

}

​

public class UserCalculator

{

    public Calculator GetOperationChoice()

    {

        Console.WriteLine("j1mm4's Calculator");

        Console.WriteLine("Choose an operation:");

        Console.WriteLine("1. Addition");

        Console.WriteLine("2. Subtraction");

        Console.WriteLine("3. Multiplication");

        Console.WriteLine("4. Division");

        Console.Write("Enter your choice (1-4): ");

​

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

        switch (choice)

        {

            case 1:

                return new AdditionCalculator();

            case 2:

                return new SubtractionCalculator();

            case 3:

                return new MultiplicationCalculator();

            case 4:

                return new DivisionCalculator();

            default:

                throw new ArgumentException("Invalid choice.");

        }

    }

​

    public void GetNumbers(Calculator calculator)

    {

        Console.Write("Enter the first number: ");

        double num1 = double.Parse(Console.ReadLine());

        Console.Write("Enter the second number: ");

        double num2 = double.Parse(Console.ReadLine());

​

        double result = calculator.Calculate(num1, num2);

        Console.WriteLine("Result: " + result);

    }

​

    public static void Main()

    {

        try

        {

            UserCalculator calculator = new UserCalculator();

            Calculator selectedCalculator = calculator.GetOperationChoice();

            calculator.GetNumbers(selectedCalculator);

        }

        catch

        {

            Console.WriteLine();

        }

    }

}