Procedure of Software Developing

Let's take an Example

Step -1
An Architect in an Building Development, It first create Prototype
(Dummy Model).

Same in Software Company having an Architect who develop the skeleton
of the Software (Dummy Model) , by using
Interfaces.

Step - 2

Then the Building develop it's core parts like Base , Levels of the
Building , Walls etc , The Core parts implements the feature mentioned
in the prototype.

Same the Software Company Develop the Base Classes , which is having
the common features . These classes implements the Prototypes
(Interfaces).

Step -3
Then the Building developer customize or Showcase the Building as per
Market Demands or Customer needs like Double roofs style or Curve
Kitchens or Round Bedrooms or Under roof lights etc.

Same the Software company as per market demands or customer needs , it
creates the child classes , who extends the Base or Core classes and
in these child classes it is having the customer specific code.