Because Model-View-Controller is a design pattern and a specific piece of code, different coders choose to implement it in different ways. Joomla is no exception.
Models are intended to handle a component's data processing. This usually although not exclusively involves storing and retrieving data from the database.
Most requests to Joomla will end up displaying HTML formatted information. The components you build will most likely consist of several screens of information that you want to display.
After Joomla begins to load your component it needs to know where to go. A controller makes it easy to define a list of places where Joomla can take a request, so let's add a controller,go to be components and com_noidacity folder in your Joomla Installation (which we have created in our earlier tutorials) and create a file called controller.php.