java - 需要比较 ArrayList 中的对象以返回最高值

Question

在这个项目中(因为我是初学者，所以使用 BlueJ)，我希望将 Climbers 添加到 ArrayList 中，其中包含他们的姓名、性别和年龄。登山者可以添加他们攀登过的山峰。带有山名和高度。

我需要在 Climber 类中添加一个方法来返回某个 Climber 攀登过的最 Alpine 峰。

要定义该方法，我是否使用它来定义它

public ArrayList<Mountain> getHighestMountain(Mountain mountainHeight)

我不确定如何检查山类中的对象进行比较。仅供引用，我还没有学习比较关键字，所以想避免使用它。

俱乐部类别:

import java.util.ArrayList;
import java.util.Scanner;
/**
 * Write a description of class Club here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class Club
{
    // An ArrayList for storing climber details.
    private ArrayList<Climber> climbers;

    /**
    * Constructor for objects of class Club
    */
    public Club()
   {
       // Initialise instance variables.
       climbers = new ArrayList<Climber>();
    }

    public void addClimber(Climber newName)
    {
        climbers.add(newName);
    }


   public Climber getClimber(String name)
   {
       Climber foundClimber = null;
       int index = 0;
       boolean searching = true;

       while(searching && index < climbers.size()) {
           Climber climber = climbers.get(index);
           if(climber.getName().equals(name)) {
                   searching = false;
                   foundClimber = climber;
                }
                else {
                    System.out.println(name + " not found");
                    index++;
                }
            }
            return foundClimber;
        }

    public void displayClimberList()
    {
        for (int item = 0; item<climbers.size();
        item++) {
            Climber climber = climbers.get(item);
            System.out.println(climber.getName() + (" ") + climber.getAge() + (" ") 
            + climber.getGender());
        }
    }

}

登山者级别:

import java.util.ArrayList;
/**
 * Write a description of class Climber here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class Climber
{
    // Instance variables.
    // The climber name.
    private String name;
    // The climber age
    private int age;
    // The climber gender.
    private String gender;
    private ArrayList<Mountain> mountains;


    /**
     * Constructor for objects of class Climber
     */
    public Climber (String newName, int newAge, String newGender)
    {
        // Initialise instance variables.
        name = newName;
        age = newAge;
        gender = newGender;
        mountains = new ArrayList<Mountain>();

    }

    /**
     * Accessor method for climber's name.
     */
    public String getName()
    {
        return name;
    }

    /**
     * Set the climber's name.
     */
    public void setName(String newName)
    {
        name = newName;
    }

    /**
     * Accessor method for climber's age.
     */
    public int getAge()
    {
        return age;

    }

    /**
     * Set the climber's age.
     */
    public void setAge(int newAge)
    {
        age = newAge;

    }

     /**
     * Set the climer's gender.
     */
   public String getGender()
   {
       return gender;
   } 

   /**
     * Accessor method for climber's gender.
     */
    public void getGender(String newGender)
    {
        gender = newGender;

    }

   public Mountain addMountain(Mountain mountain)
   {
       return mountain;
    } 

   public ArrayList<Mountain> getHighestMountain(Mountain mountainHeight)
   {
       double maxHeight = 1;
       int index = 1;
       for(int i = 0; i < mountainHeight.length; i++) {
           if(mountainHeight[i].getHeight()>maxHeight) {
               index = i;
            }
        }




    }
}

山地等级:

/**
 * Write a description of class Mountain here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class Mountain
{
    // Instance variables.
    private double height;
    private String name;

    /**
     * Constructor for objects of class Mountain
     */
    public Mountain(String mountainName, double mountainHeight)
    {
        // Initialise instance variables
        name = mountainName;
        height = mountainHeight;
    }

    /**
     * Accessor method for mountain name.
     */
    public String getName()
    {
        return name;
    }

    /**
     * Set the mountain name.
     */
    public void setName(String mountainName)
    {
        name = mountainName;
    }

    /**
     * Accessor method for mountain height.
     */
    public double getHeight()
    {
        // put your code here
        return height;
    }

    /**
     * Set the mountain height.
     */
    public void setHeight(double newHeight)
    {
        height = mountainHeight;
    }
}

我尝试返回此值，但如您所见，它不完整。

提前致谢!

Answer 1

更改:

//This does absolutely nothing. It takes a parameter and returns it.
public Mountain addMountain(Mountain mountain) {
    return mountain;
} 

public ArrayList<Mountain> getHighestMountain(Mountain mountainHeight) {
    double maxHeight = 1;
    int index = 1;
    for(int i = 0; i < mountainHeight.length; i++) {
        if(mountainHeight[i].getHeight()>maxHeight) {
            index = i;
        }
    }
}

致:

//This adds the parameter mountain to the list of mountains for this climber
public void addMountain(Mountain mountain) {
    mountains.add(mountain);
} 

//This loops over the mountains for this climber and returns the highest one. 
public Mountain getHighestMountain() {
    Mountain highestMountain = null;
    for(int i = 0; i < mountains.size(); i++) {
        if (highestMountain == null) {
            highestMountain = mountains.get(i);
        }
        else if(mountains.get(i).getHeight() > highestMountain.getHeight()) {
            highestMountain = mounts.get(i);
        }
    }
    return highestMountain;
}

您的代码示例表明缺乏对字段和变量、参数和返回类型等基本概念的理解。我建议阅读语言基础知识 here 。