A class in object-oriented programming typically contains data members (also called instance variables) and associated member functions (also called instance methods). These data members and member functions make up the class's instance fields and instance methods, respectively.
In addition to instance fields and instance methods, a class can also have class fields and class methods, which are shared by all instances of the class. Overall, a class can have four kinds of members: instance fields, instance methods, class fields, and class methods.