Several questions concerning CI4 controller

1.) I want to put the $data array outside the whole class or outside the functions (both possible in C/C++) and pass them as a parameter to the function so there is less code. How can I accomplish that in Codeigniter/php?

There is more than one way to clean up the $data code. One easy way is to create a class property.

PHP Code:

class Contact extends Controller
{
    public $data = [
     'title' => 'Contact',
     'src' => 'images/logo.jpg',
     'alt' => 'site dot net site logo',
     'heading' => 'Contact',
     'success' => 'Thank you for contacting us - we will respond to you shortly'
    ];

//  rest of class
} 


To use the property instead of this code

PHP Code:

echo view('contact/contact', $data); 


You use the $this object reference which can be thought of as being roughly equivalent to the c++ "this" pointer.

PHP Code:

echo view('contact/contact', $this->data);