Message: Undefined property: ::$input or $uri

[eluser]Unknown[/eluser]
Well after 3 hours I finally solved it.
I'm new to codeigniter soo, I had to look core codes to understand the reason.
The loader doesnt load them as "input" or "uri"

The result of

Code:

$this->load->_base_classes

that used in Controller class to load base classes is:

Code:

Array
(
    [benchmark] => Benchmark
    [hooks] => Hooks
    [config] => Config
    [utf8] => Utf8
    [urI] => URI
    [router] => Router
    [output] => Output
    [Input] => Input
    [lang] => Lang
    [loader] => Loader
)

So loader load them as "urI" and "Input"

I dont know why it does like that but using

Code:

$this->Input->post("post") | $this->urI->segment(2)

instead of

Code:

$this->input->post("post") | $this->uri->segment(2)

works at Codeigniter 2.0

Can you guys know why it does this?