Topic: [SOLVED] New to OOP

[quickstopman]

hi guys im new too using classes and objects to program stuff
i made a little bit of code
but i keep getting weird errors
what exactly am i doing wrong

Code: [Select]

<?
class user_traits {

private function Connect($id) {
$id;
$query = mysql_query("SELECT * FROM users WHERE id = '{$id}'")or die(mysql_error());
$row = mysql_fetch_array($query);
}
public function GrabUserInfo() {
$this->Connect($id);
$this->id = $id;
$this->username = $row['username'];
$this->password = $row['password'];
$this->aboutme = $row['aboutme'];
$this->age = $row['age'];
$this->email = $row['email'];
$this->ms_email = $row['ms_email'];
$this->ms_passsword = $row['ms_password'];
$this->yt_username = $row['yt_username'];
$this->yt_password = $row['yt_password'];
$this->del_username = $row['del_username'];
$this->del_password = $row['del_password'];
}
public function PostComment() {
/* Yet to be Coded */

}
}
$user = new user_traits;
$user->GrabUserInfo(12);
echo $user->id;
?>

[pocobueno1388]

What are the errors?

Also, you aren't defining your variables

Code: [Select]

<?php

class user_traits {
   var $id;
   var $password;
   //...etc


[roopurt18]

Your error is due to variable scope.

A variable declared in one method is not visible in a different method anymore than the same variable declared in one function is visible in another function.

[davestewart]

Also...

Classes are usually defined with CapsCase, whilst functions (methods) are camelCase.
Plus, you're mixing your underscore_case with camelCase.

To the class now:

Connect doesn't return a value, or set an instance variable:

Code: [Select]

$row = mysql_fetch_array($query); // grab the data
$this->user = $row; // set an instance variable

// or, you could have done this:

return $row // return the row to the GrabUserInfo() function


so how is $row defined in GrabUserInfo() ?

Is Connect() the most appropriate method name? It's not actually connecting, is it?

Next, is there any point in replicating $this->property = $row['property'] for each and every column? You could just store the mysql result as a variable:

Code: [Select]

$user->props->['property']
or iterate with a for loop to set instance variables:

Code: [Select]

foreach($row as $key => $value){
$this->$$key = $value;
}
Also, it's good practice (standard) to specify your class variables in the head of your class rather than set them in a class method. In many languages this would throw an error!

The method PostComment() is not really a property of user_traits is it? You would be best  off having this as a method of another class, perhaps a User class. I know that seems pedantic but that's teh thing with OOP - unless you're clear in your thinking, you may as well go back to procedural / spaghetti code!

I hope you don't take this as a barrage of criticism... you can pick out the technical from the practical and go from there.

Cheers,
Dave

[emehrkay]

Your error is due to variable scope.

A variable declared in one method is not visible in a different method anymore than the same variable declared in one function is visible in another function.

...
$row as defined in Connect() is not accessible in GrabUserInfo(). you can fix it a few ways.

in GrabUserInfo() do
$row = $this->Connect(); //in  your connect method you have to return $row

or

in Connect() set $row as a property of the class
$this->row = mysql_fetch_array($query);
and in GrabUserInfo() use it as $this->row