Why do I need to learn about object-oriented programming?
Because most of modern software are written using object-oriented programming languages. Using object-oriented programming as a tool and more importantly as a problem solving approach will save you a lot of time and cost when you create modern software systems.
Alright! What should I do now?
Please read this Jim Keogh and Mario Giannini (2004). OOP Demystified. McGraw-Hill book.
Is that all?
Unfortunately, the book is not sufficient for writing real world object-oriented software. Although the book already gives you the fundamental concepts of object-oriented programming the examples are only to illustrate the concepts, not to demonstrate real world situations. We recommend that you read it first because it introduces basic concepts of object-oriented programming very well. It helps you to distinguish object-oriented concepts from procedural programing concepts very clearly so that you could read other books to dig into real world object-oriented programming in a proper way. Please read this RB Whitaker (2017). The C# Player's Guide. Starbound Software book to learn how to apply object-oriented concepts to creating real world software using a specific object-oriented programming language (i.e. C# language).
After that please take a quick look at - this Joseph Albahari and Eric Johannsen (2020). C# 8.0 in a Nutshell: The Definitive Reference. O'Reilly Media book or - this Herbert Schildt (2010). C# 4.0 The Complete Reference. McGraw Hill book so that you can refer to a specific topic that needs more study when developing real world software.
I hear that there are many object-oriented programming languages such as C++, C#, Java, PHP, Objective-C, Swift, Python, Ruby. How many object-oriented programming languages do I need to know?
You should learn as many as possible. However, in this stage, we recommend that you learn only C++ or C# or Java. C++ is the most used language for creating software systems that need high performance, including games, operating systems, compilers, database management systems, web browsers, graphics editors, medical and engineering applications. Java and C# are the most used languages for creating enterprise systems. - If you are required or prefer to learn C++, please read this Bjarne Stroustrup (2013). The C++ Programming Language. Pearson Education book. - If you are required or prefer to learn Java, please read this Herbert Schildt (2019). Java: The Complete Reference. McGraw-Hill Education book.
After that please read - this Matt Weisfeld (2019). The Object-Oriented Thought Process. Pearson Education book and - this Bertrand Meyer (1997). Object-Oriented Software Construction. Prentice Hall book to get deeper understanding about object-oriented concepts and learn how to design software using object-oriented approach more efficiently.
After finishing the books please click Topic 5 - Introduction to Windows Programming to continue.