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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++.