c#之抽象类源代码

congfeng02

using System;abstract class Figure{    public Figure(double x, double y)    {        this.x = x;        this.y = y;    }    public abstract void Area();    protected double x = 0;    protected double y = 0;}class Square:Figure{    public Square(double x, double y):base(x, y)    {        Console.WriteLine("constructor of Square has been called!");    }    public override void Area()    {        Console.WriteLine("square area:" + x * y);    }}class Circle:Figure{    public Circle(double x):base(x, x)    {        Console.WriteLine("constructor of Circle has been called!");    }    public override void Area()    {        Console.WriteLine("circle area: " + Math.PI * x * x);    }}class CRunMain{    public static void Main()    {        Figure objA = new Square(10, 20);        Figure objB = new Circle(20);        objA.Area();        objB.Area();    }}