Question

I don’t know what it is called as, I believe it is instances.

Let’s say we have a “Monster” class. This class should contain “Health” value. It is set to “5” on class creation. It should also contain an unique ID value for each monster.

I think about something like this:

$monster_1 = new Monster(); //sets monster ID to 1
$monster_2 = new Monster(); //sets monster ID to 2
$monster_3 = new Monster(); //sets monster ID to 3

So, let’s say I want to calculate the total HP of all monsters.

$totalHp = $monster_1->getHp() + $monster_2->getHp() + $monster_3->getHp();

It will also work, but what if I add a new monster named $monster_4. I would have to add it to $totalHp calculation manually.

I could make an array instead of $monster variables, and calculate the $totalHp with foreach – but it looks weird…

I don’t know how it is being done in other languages.

Is there any other way to archieve this?

Ps. I’m trying to get the logic behind “http://www.scirra.com/demos/ghosttutorial/” game. You create a Monster class, and each Monster uses this class as an instance. My solution would definitely work, but I’m not sure if it is a hacky way to archieve this.

Answer 1

Create a helper class which holds a set of Monsters, maybe a MonsterTeam class;

class Monster {
     ...
}

class MonsterTeam {
    private $_monsters = [];

    public function addMonster(Monster &$monster) {
        array_push($this->_monsters, $monster);
    }

    public function getTotalHp() {
        $hp = 0;

        foreach ($this->_monsters as $monster) {
            $hp += $monster->getHp();
        }

        return $hp;
    }
}


$team = new MonsterTeam();

$monsterA = new Monster();
$team->addMonster($monsterA);

$monsterB = new Monster();
$team->addMonster($monsterB);

echo "Total HP: " . $team->getTotalHp();