PHP equivalent to C++ class static

PHP static and C++ static

[hyper_ion]

I am new to PHP in general and PHP oop specifically and it has been a while since I used C++, but I seem to recall that you could created a kind of "shared" variable across ALL instances of a class using the Static keyword in your property declaration.

Is there a way to accomplish this with PHP objects?

I need to have all instances of a class have access to a shared array.

Thank you for any assistance you can give me.

[penders]

Yes, in pretty much the same way... using the

static

keyword. The static property values are shared among all instances of the class. In this sense, they are 'class variables'.

class ClassA { 
  public static $myStaticVar = 'Hello World'; 
  private static $_myPrivateStaticVar = 'Foo Bar'; 
  public static function getPrivateVar() { 
    // Must be accessed statically (not via $this) 
    return self::$_myPrivateStaticVar; 
  } 
}

// Public static property 
echo ClassA::$myStaticVar;  // 'Hello World' 
// Private static property can be accessed via accessor method only 
echo ClassA::getPrivateVar();  // 'Foo Bar' 
// ...or via class instance 
$myInstanceA = new ClassA(); 
echo $myInstanceA->getPrivateVar();  // 'Foo Bar'

However, static variables should be used with caution. They are frowned upon by many as the do break certain OOP principles, namely encapsulation, and can make debugging harder.

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So to stick with your example, if I wanted to have each instantiated object have a unique numerical identity, could I use the following:
class ClassA {
public static $myCounter;

then in the constructor method, increment it using self::$myCounter++;
assign that to a private property and each instantiated object has an identifier.
$this->myNumber = self::$myCounter;

I get that this might not be good programming practice, but would it work?

[penders]

Yes that would work. $myCounter could be private as well if you wanted. And $myCounter should perhaps be initialised before attempting to increment it...

public static $myCounter = 0;

[hyper_ion]

Okay, thanks.