//KRIZZIA ANN C. QUINTANA

//BSIT 3-5

//Create a calculator using at least 2 from the 4 pillars of OOP.

​

​

using System;

​

// Class for basic arithmetic operations

public class Calculator

{

    protected double number1; //Encapsulation: Data hiding by making the field protected

    protected double number2;

​

    public double Number1

    {

        get { return number1; } //Encapsulation: Using properties to control access to the fields

        set { number1 = value; }

    }

​

    public double Number2

    {

        get { return number2; }

        set { number2 = value; }

    }

​

    public virtual double Calculate()

    {

        return 0; // Default implementation, can be overridden by derived classes- Polymorphism

    }

}

​

// Derived class for addition

public class Addition : Calculator

{

    public override double Calculate()

    {

        return Number1 + Number2;

    }

}

​

// Derived class for subtraction

public class Subtraction : Calculator

{

    public override double Calculate()

    {

        return Number1 - Number2;

    }

}

​

// Derived class for multiplication

public class Multiplication : Calculator

{

    public override double Calculate()

    {

        return Number1 * Number2;

    }

}

​

// Derived class for division

public class Division : Calculator

{

    public override double Calculate()

    {

        if (Number2 != 0)

        {

            return Number1 / Number2;

        }

        else

        {

            Console.WriteLine("Error!");

            return 0;

        }

    }

}

​

public class Program

{

    public static void Main(string[] args)

    {

        Console.WriteLine("Calculator");

        Console.WriteLine("Enter two numbers:");

​

        double number1 = Convert.ToDouble(Console.ReadLine());

        double number2 = Convert.ToDouble(Console.ReadLine());

​

        Calculator calc;

​

        Console.WriteLine("Select operation:");

        Console.WriteLine("1. Addition");

        Console.WriteLine("2. Subtraction");

        Console.WriteLine("3. Multiplication");

        Console.WriteLine("4. Division");

​

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

​

        switch (choice)

        {

            case 1:

                calc = new Addition(); // Inheritance: Creating an instance of a derived class

                break;

            case 2:

                calc = new Subtraction();

                break;

            case 3:

                calc = new Multiplication();

                break;

            case 4:

                calc = new Division();

                break;

            default:

                Console.WriteLine("Invalid choice. Exiting program.");

                return;

        }

​

        calc.Number1 = number1; // Encapsulation: Setting values through public properties

        calc.Number2 = number2;

​

        double result = calc.Calculate(); // Polymorphism: Calling overridden method based on the actual type of the object

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

​

        Console.ReadLine();

    }

}

​

​

​