// Cylinder.java
// 定義Cylinder類

public class Cylinder extends Circle {//圓柱繼承圓
   protected double height;  // 圓柱的高度
   
   // 構造函數
   public Cylinder()      
   {
      // 隱含的調用父類的構造函數
      setHeight( 0 );
   }

   // 構造函數
   public Cylinder( double h, double r, int a, int b )      
   {
      super( r, a, b );   // 調用父類的構造函數
      setHeight( h );
   }

   // 設置圓柱的高度
   public void setHeight( double h )
      { height = ( h >= 0 ? h : 0 ); }
   
   // 獲得圓柱的高度
   public double getHeight() { return height; }

   // 計算圓柱的底面積 (i.e., surface area)
   public double area()
   {
      return 2 * super.area() +
             2 * Math.PI * radius * height;
   }
   
   // 計算圓柱的體積
   public double volume() { return super.area() * height; }

   // 體積轉換成字符串輸出
   public String toString()
      { return super.toString() + "; Height = " + height; }

   // 返回類的名字
   public String getName() { return "Cylinder"; }
}

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 * (C) Copyright 1999 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
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