using System;

​

class Shape

{

    public void Display()

    {

        Console.WriteLine("This is a Shape");

    }

}

​

class Circle : Shape

{

    public double Radius { get; set; }

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    public Circle(double radius)

    {

        Radius = radius;

    }

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    public override void Display()

    {

        Console.WriteLine($"Circle with radius {Radius}");

    }

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    public double CalculateArea()

    {

        return Math.PI * Math.Pow(Radius, 2);

    }

}

​

class Rectangle : Shape

{

    public double Length { get; set; }

    public double Width { get; set; }

​

    public Rectangle(double length, double width)

    {

        Length = length;

        Width = width;

    }

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    public void Display()

    {

        Console.WriteLine($"Rectangle with length {Length} and width {Width}");

    }

​

    public double CalculateArea()

    {

        return Length * Width;

    }

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    public double CalculatePerimeter()

    {

        return 2 * (Length + Width);

    }

}

​

class Program

{

    static void Main()

    {

        Shape[] shapes = { new Circle(9), new Rectangle(4, 8), new Circle(2), new Rectangle(3, 7) };

​

        foreach (var shape in shapes)

        {

            shape.Display();

        }

​

        foreach (var shape in shapes)

        {

            if (shape is Circle circle)

            {

                double area = circle.CalculateArea();

                Console.WriteLine($"Area: {area}");

            }

            else if (shape is Rectangle rectangle)

            {

                double area = rectangle.CalculateArea();

                Console.WriteLine($"Area: {area}");

            }

        }

​

        foreach (var shape in shapes)

        {

            if (shape is Rectangle rectangle)

            {

                double perimeter = rectangle.CalculatePerimeter();

                Console.WriteLine($"Perimeter: {perimeter}");

            }

        }

    }

}

​