ArrayList包含兩個元素，如何只返回String元素？

Question

我對Java很新，但我覺得這是一件容易的事。這個數組列表有兩個元素...名字和分數。我想寫一個方法來打印列表中所有名字的列表，而不是分數。我知道我笑

import java.util.ArrayList; 
/** 
* Print test scrose and student names as well as he average for the class. 
*/ 
public class TestScores { 
    private ArrayList<Classroom> scores; 
    public int studentScores; 

    /** 
    * Create a new ArrayList of scores and add some scores 
    */ 
    public TestScores() { 
    scores = new ArrayList<Classroom>(); 
    } 

    /** 
    * Add a new student and a new score. 
    */ 
    public void add (String name, int score) { 
    scores.add(new Classroom(name, score)); 
    if(score > 100){ 
     System.out.println("The score cannot be more than 100"); 
    }  
    } 

    /** 
    * Return all the student names. 
    */ 
    public void printAllNames() {//this is the method. 
    for (Classroom s : scores){ 
     System.out.println(scores.get(name)); 
    } 
    } 
} 

和教室類是如何做到這一點，我只是不記得之前：

import java.util.ArrayList; 
/** 
* This class creates the names and scores of the students 
*/ 
public class Classroom { 
    public int score; 
    public String name; 

    /** 
    * Constructor for the Class that adds a name and a score. 
    */ 
    public Classroom(String aName, int aScore) { 
    score = aScore; 
    name = aName; 
    } 

    /** 
    * Return the name of the students 
    */ 
    public String returnName() { 
    return name; 
    } 

    /** 
    * Return he scores 
    */ 
    public int returnScore() { 
    return score; 
    } 
} 

Answer 1

public void printAllNames() {//this is the method. 
    for (Classroom s : scores){ 
    System.out.println(s.returnName()); 
    } 
} 

你應該在你的問題進行precice，您的列表中不包含2個元素 - 名稱和分數 - 但包含名稱和分數的多個Classroom對象。使用Java 8流

備選答案：

scores.stream().map(c -> c.returnName()).forEach(System.out::println);