Sorry for the question but I don't understand how this works:
class Person {
public static $age = 1;
public function haveBirthday() {
static::$age +=1;
}
}
$joe = new Person;
$joe->haveBirthday();
echo Person::$age;
What I'm not understanding is this:
public function haveBirthday() {
static::$age +=1;
}
Isn't supposed to return $age otherwise the value is lost? Why is it still working?
Thanks!
You've defined it as static, which means those are class level variables instead of instance level.
So when you call $joe->haveBirthday(); it updates the class level variable of the Person class which can accessed using Person::$age;.
Static variables does not need to be returned, you can access it directly from Class.
public static $age = 1; suggests this is a static property, which means this as a class property, not an instance's.
The method haveBirthday() does not return anything, it simply increase the static variable $age.
A static variable is shared by all instances of this classes. So it is not a good idea in your case, as all persons will have the same age.
class Person {
public static $age = 1;
public function haveBirthday() {
static::$age +=1;
}
}
$joe = new Person;
$jane = new Person;
$joe->haveBirthday(); // +1 => 2
$jane->haveBirthday(); // +1 => 3
echo Person::$age; // Will return 3
Test it here.
