Objects , as opposed to structures , incorporate both data and behavior . But there is more to that. Several themes underlie object-oriented technology. Classes and instances Objects are instances of classes. A class is a definitive description of a group of objects with similar properties and behaviors.
Classes are abstract, objects are concrete.
Objects are aware of their class identity. Polymorphism Polymorphism is the kindred to the incorporation of data and behavior. The object knows how to do the job. Inheritance Inheritance is a mechanism for sharing similarities among classes while preserving their differences. In the OO terminology, the individual pieces of data are known as attributes while the operations that objects carry out are known as methods .