07.11.IntroductionToClasses__1_

Computer Science I COSC 1020 Overview

• Institution: Georgetown University

Introduction to Classes

• Context: Understanding the C++ programming paradigm focusing on Classes and Object-Oriented Programming (OOP).

• Processor Performance: Explains the computation pace of x64 processors involved in running complex systems like XNU kernel and browsers.

• Key Concepts Covered:

  • Introduction to objects

  • Abstract Data Types (ADT)

  • Object-oriented programming principles

  • Class member functions

  • Object lifecycle: Creation and destruction

  • Operators in context of classes

Chapter Breakdown

• Abstract Data Types (7.1)

• Object-oriented programming (7.2)

• Introduction to classes (7.3)

• Creating and using objects (7.4)

• Member Functions: Definition and Implementation (7.5; 7.11)

• Private Member Functions (7.8)

• Constructors and Destructors:

  • Constructors: Initialize objects (7.6)

  • Destructors: Clean up when objects are destroyed (7.7)

  • Copy Constructors: Handle copying of objects (11.5)

  • Passing Objects: Parameters in functions (7.9)

• Class Operators:

  • Friend Classes: Access private members (11.3)

  • Operator Overloading: Customize operator behavior (11.6)

  • Type Conversion Operators: Handle data type interchange (11.8)

Introduction to Objects

C++ Data Types

• Primitive Data Types:

  • int (short/long)

  • float/double

  • char

  • bool

• Standard Library Types:

  • string

  • vector<>

• Real-world Data Complexity: Emphasis on varying structures of real-world data.

Abstractions

• Definition: General models representing the essence of data or processes.

• Quote: "All models are wrong. Some models are useful.” - George Box

Abstract Data Types (ADTs)

• Definition: Programmer-defined types encapsulating both data and behavior.

• Characteristics:

  • Shape of data (legal values)

  • Operations that can be performed on the data

Purpose of ADTs

• Provide a better representation of real-world problems than primitive types.

• Encapsulate behaviors and hide internal workings, allowing for data integrity and abstractions.

Examples of ADTs in C++

• String Class:

  • Represents strings as character sequences, simplifies usage without deep implementation understanding.

• Vector Class:

  • Dynamic arrays capable of resizing.

• Mathematical Complex Numbers:

  • Defined by real and imaginary components.

Procedural vs Object-Oriented Programming

Procedural Programming

• Focus on behaviors, solving problems through function-centric steps.

Object-Oriented Programming (OOP)

• Focus on participants (objects) in a problem, emphasizing their attributes and capabilities.

Key Terminology in OOP

• Class: Blueprint for creating objects, encapsulating data attributes and methods.

• Object: Instance of a class.

• Attribute: Data stored in an object.

• Method: Functions that define actions objects can perform.

Principles of OOP

• Encapsulation: Grouping data and methods that operate on that data within a class.

• Data Hiding: Concealing class internals from the user to prevent improper behavior.

Class Declaration in C++

• Keywords and syntax for declaring classes.

• Members include attributes and methods.

• Access levels: public/protected/private members.

Member Functions and Access Control

• Access Levels: Determines visibility of members to code.

• Private Members: Accessible only within class functions, promoting encapsulation practices.

Creating and Managing Objects

• Instantiation: Creating an object from a class, its own copy of member variables.

• Accessor Operator: Using “.” to reference objects' attributes and methods.

Constructors and Destructors

• Constructors: Special functions invoked at object creation for initialization.

• Destructors: Functions called when an object is destroyed to clean up resources.

Copy Constructors

• Define behavior for copying objects ensuring independent instances (deep copy).

Memberwise Assignment

• Automatically provided behavior of copy constructors & assignment operators; may need custom implementation for resource management.

Operator Overloading in C++

• Mechanism to redefine standard operators for user-defined types, e.g., operator+ for adding complex numbers.

Stream Overloading

• Operators: For example, << for output and >> for input for objects.

Concluding Takeaways

• Major principles of OOP: encapsulation, data hiding, class structure, and operators for enhancing functionality.

• Understanding of constructors, destructors, and copy constructors in memory management.

• Importance of syntactical rules for seamless programming in C++.