C#使用多態求方形面積周長和圓的面積周長

  class class1{public static void Main(string[] args){//使用多態求矩形面積與周長和圓的面積與周長Shape cl = new Circle(5);double clarea = cl.GetArea();double clpar = cl.GetPerimeter();Console.WriteLine("這個圓的面積是{0},周長是{1}", Math.Round(clarea, 2), Math.Round(clpar, 2));Shape sq = new Square(5, 10);double sqarea = sq.GetArea();double sqpar = sq.GetPerimeter();Console.WriteLine("這個方形的面積是{0},周長是{1}", Math.Round(sqarea, 2), Math.Round(sqpar, 2));Console.ReadKey();}}//聲明一個抽像類public abstract class Shape{public abstract double GetArea();public abstract double GetPerimeter();}class Circle:Shape{private double _r;public double R{get {return _r;}set {_r = value;}}public Circle(double r){this.R = r;}public override double GetArea(){return Math.PI * this.R * this.R;}public override double GetPerimeter(){return 2 * Math.PI * this.R;}}class Square : Shape{private double _height;private double _width;public double Height{get{return _height;}set{_height = value;}}public double Width{get {return _width;}set {_width = value;}}public Square(double w, double h){this.Height = h;this.Width = w;}public override double GetArea(){return this.Width * this.Height;}public override double GetPerimeter(){return (this.Width + this.Height) * 2;}}

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