usage of multiple properties in php

I am trying to learn oop in php, but the below code is not working could someone provide an a开发者_StackOverflowlternate answer?

<?php
    class abc {
        public $a = 1;
        $b = $a;

        function foo(){
            //some function..
        }

    }
?>

I want to assign value of variable "a" to variable "b".

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You can assign the value of $a to $b like so: $this->b = $this->a within the __construct method which gets called upon object creation, assuming you're running PHP 5.

---

Not exactly what you've asked for but it might (or might not) solve your problem:
You can define a constant that is used to initialize both members, $a and $b.

<?php
class abc {
    const defaultValue = 1;
    public $a = self::defaultValue;
    public $b = self::defaultValue;

    function foo(){
        //some function..
    }
}

$abc = new abc;
var_dump($abc);

prints

object(abc)#1 (2) {
  ["a"]=>
  int(1)
  ["b"]=>
  int(1)
}