Object Oriented Programing (OOP) is the most popular programming paradigm in Computer Science. It's main building blocks are objects and classes. A class is a blueprint from which objects are created - objects are instances of classes.
You can think of a class as a category, as well. Each class can have attributes/properties which contain different values and describe the states of a class' instance (object). It also contains functions (called methods), which typically change these properties and thus, the state of either the invoking instance or other instances, or return information about it/its neighbors.
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