如何用开闭原理C#计算面积

// 定义一个抽象类或接口
public abstract class Shape
{
    public abstract double CalculateArea();
}

// 实现具体的形状类
public class Rectangle : Shape
{
    public double Width { get; set; }
    public double Height { get; set; }

    public override double CalculateArea()
    {
        return Width * Height;
    }
}

public class Circle : Shape
{
    public double Radius { get; set; }

    public override double CalculateArea()
    {
        return Math.PI * Radius * Radius;
    }
}

// 使用示例
public class Program
{
    public static void Main(string[] args)
    {
        Shape rectangle = new Rectangle { Width = 5, Height = 3 };
        double rectangleArea = rectangle.CalculateArea();
        Console.WriteLine("矩形的面积：" + rectangleArea);

        Shape circle = new Circle { Radius = 2 };
        double circleArea = circle.CalculateArea();
        Console.WriteLine("圆形的面积：" + circleArea);
    }
}