你知道如何计算OOP中的平均值吗？

Question

我知道如何在过程编程中计算平均值，除了在oop中我不知道如何做这个：

我有2个对象，我想计算一下平均年龄：

class Main {
  public static void main(String[] args) {
    List<Player> players = new ArrayList<Player>();

    players.add(new Player("Eric", 31, true));
    players.add(new Player("Juliette", 28, false));

在我的班上，我有这个

public class Player {

  public String name;
  public int age; 
  public boolean sex;

  public Player(String name, int age, boolean sex){
    this.name = name;
    this.age = age;
    this.sex = sex;
  }

在我的CalculateAverage（）方法中，我看不出如何做这个？我的循环有问题。

public static void CalculateAverage(List <Player> players){
    int sumAge =  0;

    for(Player player : players){
            
    }
  } 

Answer 1

方法一：

在循环中，求和所有年龄，然后除以年龄总数

 List<Player> players = new ArrayList<Player>();

    players.add(new Player("Eric", 31, true));
    players.add(new Player("Juliette", 28, false));
    double sum = 0;
    for(Player player : players){
        sum = sum +player.age;
    }
    double average = sum/players.size();
    System.out.println(average);
   

方法二：

利用Java 8条溪流。将列表转换为流(players.stream())，然后将您的年龄映射为double(MapToDouble())，然后调用average

 List<Player> players = new ArrayList<Player>();
    players.add(new Player("Eric", 31, true));
    players.add(new Player("Juliette", 28, false));
    final OptionalDouble optionalAverage = players.stream().mapToInt(Player::getAge).average();
    System.out.println(optionalAverage);