求矩形和圆形的面积周长

以下是使用C#和Python分别求解矩形和圆形的面积和周长的例子：

C#代码：

using System;

public abstract class Shape
{
    public abstract double GetArea();
    public abstract double GetPerimeter();
}

public class Rectangle : Shape
{
    private double length;
    private double width;

    public Rectangle(double l, double w)
    {
        length = l;
        width = w;
    }

    public override double GetArea()
    {
        return length * width;
    }

    public override double GetPerimeter()
    {
        return 2 * (length + width);
    }
}

public class Circle : Shape
{
    private double radius;

    public Circle(double r)
    {
        radius = r;
    }

    public override double GetArea()
    {
        return Math.PI * radius * radius;
    }

    public override double GetPerimeter()
    {
        return 2 * Math.PI * radius;
    }
}

class Program
{
    static void Main(string[] args)
    {
        // 使用多态求矩形的面积和周长，求圆形的面积和周长
        Shape shape = new Circle(5);
        double area = shape.GetArea();
        double perimeter = shape.GetPerimeter();
        Console.WriteLine("圆形的周长是{0}，面积是{1}", perimeter, area);

        shape = new Rectangle(3, 4);
        area = shape.GetArea();
        perimeter = shape.GetPerimeter();
        Console.WriteLine("矩形的周长是{0}，面积是{1}", perimeter, area);
    }
}

Python代码：

import math

class Shape:
    def get_area(self):
        pass

    def get_perimeter(self):
        pass

class Rectangle(Shape):
    def __init__(self, length, width):
        self.length = length
        self.width = width

    def get_area(self):
        return self.length * self.width

    def get_perimeter(self):
        return 2 * (self.length + self.width)

class Circle(Shape):
    def __init__(self, radius):
        self.radius = radius

    def get_area(self):
        return math.pi * self.radius * self.radius

    def get_perimeter(self):
        return 2 * math.pi * self.radius

# 使用多态求矩形的面积和周长，求圆形的面积和周长
shape = Circle(5)
area = shape.get_area()
perimeter = shape.get_perimeter()
print("圆形的周长是{0}，面积是{1}".format(perimeter, area))

shape = Rectangle(3, 4)
area = shape.get_area()
perimeter = shape.get_perimeter()
print("矩形的周长是{0}，面积是{1}".format(perimeter, area))