C#多态问题中的抽象类问题

namespace 实验二
{
class Program
{
static void Main(string[] args)
{
Rectangle Juxing = new Rectangle();
Console.WriteLine("请输入长度：");
Juxing.chang = float.Parse(Console.ReadLine());
Console.WriteLine("请输入宽度：");
Juxing.kuan = float.Parse(Console.ReadLine());
Console.WriteLine("矩形面积：");
Juxing.show();

        Circle yuan = new Circle();

     Console.WriteLine("请输入半径：");
     yuan.r = float.Parse(Console.ReadLine());    
     Console.WriteLine("圆面积：");
     yuan.show();
     Console.ReadLine();




    }

}
 public    class Rectangle : Shape
{
    public float chang;
    public float kuan;
    public float juxingArea()
    {
        return chang * kuan;
    }
    public override void show()
    {
     Console .WriteLine("{0}" ,  juxingArea());
    }

}
public  class Circle : Shape
{
    public float r;
    public double yuanArea()
    {
        return 3.14 * r * r;
    } 
    public override void show()
    {
        Console.WriteLine("{0}", yuanArea());
    }
}

}
namespace 实验二
{
public abstract class Shape
{

    public abstract void show();




}

}这是完整代码
当我执行这个程序的时候 ，输入长宽和半径，不会输出面积，为什么呢

不知道你什么问题，我这里可以输出啊

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Q710430
{
    class Program
    {
        static void Main(string[] args)
        {
            Rectangle Juxing = new Rectangle();
            Console.WriteLine("请输入长度：");
            Juxing.chang = float.Parse(Console.ReadLine());
            Console.WriteLine("请输入宽度：");
            Juxing.kuan = float.Parse(Console.ReadLine());
            Console.WriteLine("矩形面积：");
            Juxing.show();
            Circle yuan = new Circle();
            Console.WriteLine("请输入半径：");
            yuan.r = float.Parse(Console.ReadLine());
            Console.WriteLine("圆面积：");
            yuan.show();
            Console.ReadLine();
        }

    }
    public abstract class Shape
    {
        public abstract void show();
    }

    public class Rectangle : Shape
    {
        public float chang;
        public float kuan;
        public float juxingArea()
        {
            return chang * kuan;
        }
        public override void show()
        {
            Console.WriteLine("{0}", juxingArea());
        }

    }
    public class Circle : Shape
    {
        public float r;
        public double yuanArea()
        {
            return 3.14 * r * r;
        }
        public override void show()
        {
            Console.WriteLine("{0}", yuanArea());
        }
    }
}