The term ‘object’, however, refers to an actual instance
of a class. Every object must belong to a class. Objects are created
and eventually destroyed – so they only live in the program for a
limited time. While objects are ‘living’ their properties may also be
An example will help clarify what we’ve said. Suppose
we have a class called ‘Animal’. All Animals have bodies and brains.
So, this general ‘template’ of an Animal does not change.
An instance of the Animal class would be a specific
animal – like a lion, a cat, or a zebra. These instances of the
Animal class would be called objects. Whereas the Animal class is a
general concept, the instances of that class – the lions, cats, etc –
take that general concept and create a real instance of it.
The term ‘class’ refers to the actual written piece of code in which the
class is defined. A class is a static piece of code that consists of
attributes which don’t change during the execution of a program – like
the method definitions within a class.
5 API (Application programming interface)
An application programming interface (API) specifies how some software components should interact with each other.