Characteristics of OOP

An object-oriented program has four fundamental characteristics:

• Abstraction defines new data types
• Encapsulation designs a data type's representation and its behavior in one encapsulated entity.
• Inheritance derives a new data type from an existing one.
• Polymorphism customizes the behavior of a derived data type, a function, or an operator.

Some authors combine the first and second of these characteristics, resulting in only three fundamental characteristics.