In reply to kireeti1192:
What is the use of Abstract Class?
Is this the only reason why abstract class is used, “Abstract class is used wherever instantiation is not required” ?
You can think of Abstract class as a template. You cannot use directly template unless you add sufficient details to it, in which case the class becomes a concrete class.
Abstract class can (and is) also be used to create class variable that points to handles.
As the abstract class is at the top of the class hierarchy, it can actually point to objects of any of the derived classes. This makes the code (that uses abstract class variable) less susceptible to changes in the class hierarchy.
Anyway, OOPS is a very big topic. You have to read through materials even to understand what is being explained here.