2 Classes and Objects Free Online FlashCards

What is a class in object-oriented programming?

A class is a programmer-defined type that specifies the structure and behavior its objects will have.

What is an object, or instance?

An object is a concrete runtime value created from a class; it is also called an instance of that class.

What does instantiation mean?

Instantiation is the process of creating an object from a class.

What is an attribute?

An attribute is a named value associated with a class or object, such as `checking.balance`.

What does an object's state describe?

An object's state is the collection of its attribute values at a particular moment.

What is a method?

A method is a function associated with a class that defines an operation an object can perform or have performed on its behalf.

What is the role of `self` in a Python instance method?

In Python, an instance method conventionally receives the instance as its first parameter, usually named `self`; Python supplies it automatically for an object call.

How do class and instance attributes differ?

A class attribute is shared by a class or its instances, while an instance attribute belongs to one particular object.

Why can mutable class attributes be dangerous?

A mutable class attribute, such as a list or dictionary, is shared, so a change through one instance can be visible through other instances.

What does Python's `__init__()` do?

In Python, `__init__()` is an initializer called automatically after a new instance is created to establish its initial state.

What identifies a Java constructor?

A Java constructor has the same name as its class and has no return type; it is invoked during object creation.

How do object identity and equality differ?

Identity asks whether two references designate the exact same object; equality asks whether their values compare as equal.