abstractinheritancetest.java

《Java面向对象程序设计》例子源代码.轻松学习书本.

//AbstractInheritanceTest.java
import java.text.DecimalFormat;
import javax.swing.JOptionPane;
public class AbstractInheritanceTest {
   public static void main( String args[] ){
      DecimalFormat twoDigits = new DecimalFormat( "0.00" );
      Point point = new Point( 7, 11 );  
      Circle circle = new Circle( 22, 8, 3.5 );  
      Cylinder cylinder = new Cylinder( 20, 30, 3.3, 10.75 );  
      String output = point.getName() + ": " + point + "\n" +
         circle.getName() + ": " + circle + "\n" +
         cylinder.getName() + ": " + cylinder + "\n";
      Shape arrayOfShapes[] = new Shape[ 3 ];  //声明Shape类型的数组
      arrayOfShapes[ 0 ] = point;				//将Point对象的引用point赋给Shape类型的数组元素1
      arrayOfShapes[ 1 ] = circle;				//将Circle对象的引用circle赋给Shape类型的数组元素2
      arrayOfShapes[ 2 ] = cylinder;			//将Cylinder对象的引用cylinder赋给Shape类型的数组元素3
      for ( int i = 0; i < arrayOfShapes.length; i++ ) {
         output += "\n\n" + arrayOfShapes[ i ].getName() + ": " + 
            arrayOfShapes[ i ].toString() + "\nArea = " +
            twoDigits.format( arrayOfShapes[ i ].getArea() ) +
            "\nVolume = " +
            twoDigits.format( arrayOfShapes[ i ].getVolume() );
      }
      JOptionPane.showMessageDialog( null, output );  
      System.exit( 0 );
   }
}