shapetest.java

来自「java learn PPT java learn PPT java learn」· Java 代码 · 共 72 行

     abstract class AbstractShape
     {
          public abstract double area();
          public abstract double perimeter();

          static double totalArea(final AbstractShape[] shapes)
          {
               double total = 0.0;
          
               for(int i = 0; i < shapes.length; i++) 
               {     total += shapes[i].area();
               }
               return total;
          }

          static double totalPerimeter(final AbstractShape[] shapes)
          {
               double total = 0.0;
          
               for(int i = 0; i < shapes.length; i++) 
               {     total += shapes[i].perimeter();
               }
               return total;
          }
     }    // class AbstractShape

     class Circle extends AbstractShape 
     {
          private double radius;

          public Circle(double r) 
          {     radius = r;
          }
          public double area() 
          {     return Math.PI * radius * radius;
          }
          public double perimeter() 
          { return (2.0 * Math.PI * radius);
          }
     }

     class Rectangle extends AbstractShape 
     {
          private double width;
          private double height;

          public Rectangle(double w, double h)
          {     width  = w;
                height = h; 
          }
          public double area()
          {     return (width * height);
          }
          public double perimeter()
          {     return (2.0 * (width + height));
          }
     }

     public class ShapeTest 
     {
           public static void main(String[] args) 
           {     
                AbstractShape[] myShapes = 
                {     new Rectangle(10.0, 20.0),
                      new Circle(5.5),
                      new Rectangle(0.1, 0.2)
                }; 
                System.out.println(AbstractShape.totalArea(myShapes));
                System.out.println(AbstractShape.totalPerimeter(myShapes));
           }
     }