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@NogDogFeb 14.2009 — #Remember that PHP allows you to set undefined class variables at run-time. So when you set the $_number2 variable in the child class, it is being created at that time as a public variable. To see what I mean, run this:
Output:
@NogDogFeb 14.2009 — #It's one of those things that is both a feature and a bug, depending on how you want to look at it. ?@NogDogFeb 15.2009 — #Setting the value does not cause a notice. It only generated a notice in my sample script because I tried to echo it before ever setting it, demonstrating that at that point in the script there was no such variable in that object. Then after I set it, it did exist, and the second echo did not generate a notice.
In other words, if you assign a value to a class variable that does not exist, then it is created at that time. In your script, since the child class did not inherit the private variable, it did not exist at all in the object instantiated from that child class. It is not a case of the variable existing but not being accessible, it does not exist at all in the child class. So when you assign a value to it, it is created in that object at that moment as an object variable with public access.
protected or private? which one to use ..
hello,
I have a class called [B]Object[B]Person extends Object
in the base class i want to use members (properties) which can be used in the Person class
[code=php]class Object {
protected $_number1;
private $_number2;
{
class Person extends Object{
public function __construct($n1,$n2){
$this->_number1 = $n1;
$this->_number2 = $n2;
}
}
properies number1 and number2 are both accessible!! so what is difference?
Thank u
kind regards
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@NogDogFeb 14.2009 — #Remember that PHP allows you to set undefined class variables at run-time. So when you set the $_number2 variable in the child class, it is being created at that time as a public variable. To see what I mean, run this:[code=php]
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
class foo
{
public $var1 = 1;
protected $var2 = 2;
private $var3 = 3;
}
class bar extends foo
{
public function test()
{
printf("%d<br>%d</br>%d", $this->var1, $this->var2, $this->var3);
}
public function set()
{
$this->var3 = 33;
}
}
$obj = new bar();
echo "<p>".$obj->test()."</p>"; // will generate notice-level warning
$obj->set();
echo "<p>".$obj->test()."</p>";
[/code]Output:
Notice: Undefined property: bar::$var3 in C:wampwwwtesttest.php on line 16
1
2
0[color=blue][variable was undefined, so ouput as 0 instead of 3 by printf()][/color]
1
2
33[color=blue][now it is set (at run-time) as a public variable][/color]
[/quote]
0
@NogDogFeb 14.2009 — #It's one of those things that is both a feature and a bug, depending on how you want to look at it. ?0
@NogDogFeb 15.2009 — #In other words, if you assign a value to a class variable that does not exist, then it is created at that time. In your script, since the child class did not inherit the private variable, it did not exist at all in the object instantiated from that child class. It is not a case of the variable existing but not being accessible, it does not exist at all in the child class. So when you assign a value to it, it is created in that object at that moment as an object variable with public access.