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cs5/5_4/Program.cs

@@ -0,0 +1,60 @@
+namespace _5_4
+{
+    public abstract class Shape
+    {
+        protected string name;
+        public Shape(string name)
+        {
+            this.name = name;
+        }
+        public abstract void Show();
+        public abstract double Area();
+    }
+    public class Rectangle : Shape
+    {
+        protected double width;
+        protected double height;
+        public Rectangle(string name, double width, double height) : base(name)
+        {
+            this.width = width;
+            this.height = height;
+        }
+        public override void Show()
+        {
+            Console.WriteLine("Rectangle: {0} , area :{1}", name, width * height);
+        }
+        public override double Area()
+        {
+            return width * height;
+        }
+    }
+    public class Circle : Shape
+    {
+        protected double radius;
+        public Circle(string name, double radius) : base(name)
+        {
+            this.radius = radius;
+        }
+        public override void Show()
+        {
+            Console.WriteLine("Circle: {0} , area :{1}", name, Math.PI * radius * radius);
+        }
+        public override double Area()
+        {
+            return Math.PI * radius * radius;
+        }
+    }
+    public class Program
+    {
+        static void Main(string[] args)
+        {
+            Shape[] s = { new Rectangle("小矩形",1.0,2.0),
+                         new Circle("大源",5.0),
+                        };
+            foreach (Shape shape in s)
+            {
+                shape.Show();
+            }
+        }
+    }
+}