Call to a member function on a non-object

[pejman_view]

Hello,

First of all , I appreciate from your perfect forum,I just joind. and This is my first post.

I study some tutorial video on PHP-OOP but I faced some errors and misunderstood.

1- The misunderstood is below:

$user = User::find_by_id(1);
echo $user->full_name();

the find_by_id() method is a statical method but full_name is not so. hence we need to instantiate User class but in that video, he does not instantiate it.

2- The error I faced it :
Fatal error: Call to a member function full_name() on a non-object

I write the script like him but he could run it by i could not. I ask the masters, help me to find my mistake.

meanwhile I attached my script and Kevin's script to this post.