无法弄清楚为什么我一直无法找到符号编译错误

Question

public class CylinderList
{
 private String listName = "";
private ArrayList<Cylinder> cyll = 
         new ArrayList<Cylinder>();

public CylinderList(String listNameIn, 
         ArrayList<Cylinder> cyllIn)                           
{
  listName = listNameIn;
  cyll = cyllIn;
}

public String getName()
{
  return listName;
}

public int numberofCylinders()
{
  return cyll.size();      
}

public double totalArea()
{
  double Area = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  while (index < cyll.size())
  {
     Area += cyll.get(index).getArea();

     index++;
  }
  return Area;
}

public double totalVolume()
{
  double Volume = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  while (index < cyll.size())
  {
     Volume += cyll.get(index).getVolume();

     index++;
  }
  return Volume;
}

public double totalHeight()
{
  double Height = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  while (index < cyll.size())
  {
     Height += cyll.get(index).getHeight();

     index++;
  }
  return Height;
}

public double totalDiameter()
{
  double Diameter = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  while (index < cyll.size())
  {
     Diameter += cyll.get(index).getDiameter();

     index++;
  }
  return Diameter;
}

public double averageArea()
{
  double aArea = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  else 
  {
     aArea += totalArea() / cyll.size();
     return aArea;
  }
}

public double averageVolume()
{
  double aVolume = 0;
  int index = 0;

  if (cyll.size() == 0)
  {
     return 0;
  }

  else 
  {
     aVolume += totalVolume() / cyll.size();
     return aVolume;
  }
}
}

我一直在getArea，getVolume，getHeight和getDiameter上找不到符号编译时错误。我只是一个初学者，所以任何帮助将不胜感激。我将其与另一个文件一起使用但我无法解决问题

import java.text.DecimalFormat;
public class Cylinder
{

// Fields
private String label = "";
private double radius; 
private double height;
/**
*@param labelIn Command line arguements (not used).
*@param radiusIn Command line arguements (not used).
*@param heightIn Command line arguements (not used).
*/

public Cylinder(String labelIn, double radiusIn, double heightIn) 

{      
  label = labelIn;
  radius = radiusIn;
  height = heightIn;
}
/**
*@return String representation of label. 
*/
public String getlabel()
{
  return label;
}
/**
*@param labelIn The formal parameter for the set label method.
*@return checks to see if labelIn exist.
*/ 
public boolean setlabel(String labelIn)
{
  if (labelIn == null)
  {
     return false;
  }
  else 
  {
     label = labelIn.trim();
     return true;
  }
  }
  /**
  *@return a method to display a double radius.
  */ 
  public double getRadius()
  {
  return radius;
  }
  /**
 *@param radiusIn the formal parameter for the setRadius method.
 */ 
 public void setRadius(double radiusIn)
 { 
  radius = radiusIn;
 }
 /**
 *@return a method to display a double height.
 */ 
 public double getHeight()
 {
  return height;
 }
 /**
 *@param heightIn the formal parameter for the setHeight method.
 */ 
 public void setHeight(double heightIn)
 { 
  height = heightIn;
 }
 /**
 *@return displays diameter when method is called.
 */ 
 public double diameter()
 {
  return radius * 2;
 }
 /**
 *@return displays circumference when method is called.
 */ 
 public double circumference()
 {
  return Math.PI * radius * 2;
 }
 /**
 *@return displays area when method is called.
 */ 
 public double area()
 {
  return 2 * Math.PI * radius * radius + 2 * Math.PI * radius * height;
 }
 /**
 *@return displays volume when method is called.
 */ 
 public double volume()
 {
  return Math.PI * radius * radius * height;
 }
 /**
 *@return displays cylinder information.
 */ 
 public String toString()
 {
  DecimalFormat fmt = new DecimalFormat("#,##0.0##");

  return 
     ("Enter label, radius, and height for a cylinder."
           + "\n\tlabel: " +  label
           +  "\n\tradius: " + fmt.format(getRadius())
           + "\n\theight: " + fmt.format(getHeight()) 
           + "\n\"" + label + "\" is a cylinder with radius = " 
           + fmt.format(getRadius())
           + " units and height = " + fmt.format(getHeight()) + "     units," 
           + "\nwhich has diameter = " + fmt.format(diameter())  
           + " units, circumference = "
           + fmt.format(circumference()) + " units,"
           + "\narea = " + fmt.format(area()) + " square units,"
           + " and volume = " + fmt.format(volume()) + " cubic  units.");


 }
 }

这是Cylinder。

Answer 1

Cylinder类的代码必须可供编译器使用，因为CylinderList类正在引用它。编译器无法在正在编译的java文件中找到它。