How to compare the value of an age on 2 objects?

Question

I know that the subject exists on StackOverFlow, but I don't understand really the logic. Comparing two class objects with a method

I have a class Player with 3 variables:

  ...
  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;
  }

  public void display(int number){
    System.out.println("-----------------------");
    System.out.println("Number : " + number);
    System.out.println("Name : " + name);
    System.out.println("Age : " + age);
    System.out.println("Sex : " + sex);

  }
  ...

Then, I create 2 objects into my file Main as below:

List<Player> players = new ArrayList <Player>();
players.add(new Player("Eric", 31, true));
players.add(new Player("Juliette", 27, false));

I would like to compare the variable age from the object1 to the object2 and after, I have to display the name of the Player who is the oldest player. So here, it's Eric.

I am stuck into my method displayOldestAge() I don't understand how to compare 2 ages by adding the name of the player.

public void displayOldestAge(int[] arrayPlayer){
    int oldestAge = 0;

    for(int i=0; i<arrayPlayer.length; i++){
      if(arrayPlayer[i].age > oldestAge.age){
        oldestAge = arrayPlayer[i];
      }
    }
    System.out.println("The player oldest age is " + ???);
  }

`arrayPlayer` is an int array, not a `Player` array. This will not compile. — Liftoff, Apr 13 '21 at 16:49
`oldestAge` is an integer also, so `oldestAge.age` doesn't mean anything. Also if you have a `List`, why is the input to the `displayOldestAge` a normal array? — Henry Twist, Apr 13 '21 at 16:50

score 1 · Accepted Answer · answered Apr 13 '21 at 16:56

You've got many issues with your displayOldestAge method. Here's a revised one.

Key changes:

Your input param should be an array of Player objects, not integers.
There's no need to track the oldest age, just the oldest player.
If the array is empty, it should exit.
Echo the oldest player's info at the end of the method with the stored oldestPlayer.

public void displayOldestAge(Player[] arrayPlayer){

    if(arrayPlayer.length == 0) return;

    Player oldestPlayer = arrayPlayer[0];

    for(int i = 1; i < arrayPlayer.length; i++)
    {
        if(arrayPlayer[i].age > oldestPlayer.age)
        {
            oldestPlayer = arrayPlayer[i];
        }
    }

    System.out.println("The player oldest age is " + oldestPlayer.name + ", Age: " + oldestPlayer.age)
}

Thank you for your explanations. I have an ask. what do you call the displayOldestAge() method into the file main ? I have this : `displayOldestAge(players);` but I have an error message --> `Main.java:23: error: cannot find symbol displayOldestAge(players);` — , Apr 13 '21 at 17:04
You have to call it either from within the class itself, or make it static and call it under the namespace of the class. — Liftoff, Apr 13 '21 at 17:50

score 0 · Answer 2 · answered Apr 13 '21 at 16:56

I can see that OldestAge is an int primitive. And you want to compare with Player.age which is not correct. Compare oldestAge with player.age and have a reference of Player object created and assign that to array player[i]. And now printing reference.name should be giving the right result.

How to compare the value of an age on 2 objects?

2 Answers2