Classes and Object-Oriented Programming

If you are taking this course, you have probably used object-oriented programming (OOP) previously in another language. If it's been a while since you've used OOP, OOP is a style of coding that collects related data (object attributes) and functions (object methods) together to form a single data structure, called an object. This allows that collection of attributes and methods to be used repeatedly in your program without code repetition.

In C++ the attributes and methods that make up an object are specified in a code class, and each object in the program is an instance of that class.

This concept is intended to provide you with the basic syntax for writing classes in C++. In this Foundations course, you will not need to write your own classes for the project, but you will be modifying existing classes in the code. You will be writing your own classes in the next course of this Nanodegree: Object-Oriented Programming.

Workspace

This section contains either a workspace (it can be a Jupyter Notebook workspace or an online code editor work space, etc.) and it cannot be automatically downloaded to be generated here. Please access the classroom with your account and manually download the workspace to your local machine. Note that for some courses, Udacity upload the workspace files onto https://github.com/udacity, so you may be able to download them there.

Workspace Information:

Default file path:
Workspace type: jupyter
Opened files (when workspace is loaded): n/a

Inheritance

It is possible for a class to use methods and attributes from another class using class inheritance. For example, if you wanted to make a Sedan class with additional attributes or methods not found in the generic Car class, you could create a Sedan class that inherited from the Car by using the colon notation:

class Sedan : public Car {
    // Sedan class declarations/definitions here.
};

By doing this, each Sedan class instance will have access to any of the public methods and attributes of Car. In the code above, these areIncrementDistance() and PrintCarData(). You can add additional features to the Sedan class as well. In the example above, Car is often referred to as the parent class, and Sedan as the child or derived class.

A full discussion of inheritance is beyond the scope of this course, but you will encounter it briefly in the project code later. In the project code, the classes are set up to inherit from existing classes of an open source code project. You won't need to use inheritance otherwise, but keep in mind that your classes can use all of the public methods and attributes of their parent class.

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