2.1: Programming Language Design
2.1.1: Object-Oriented vs. Procedural
Read the PDF titled, "Session 1 Handout: Object-Oriented Programming," and watch "Recitation 1: Object-Oriented Programming."
2.1.2: Advantages/Disadvantages of OO Programming
Please read this article about object-oriented programming.
2.1.3: Examples
2.1.3.1: Java
Please read this article. The Java Tutorials are practical guides for programmers who want to use the Java programming language to create applications. They include hundreds of complete, working examples, and dozens of lessons. Groups of related lessons are organized into "trails." This tutorial from Oracle gives an overview of a class in Java.
2.1.3.2: Python
Please read this article. Please note that the concept of classes is the same in different languages, though the syntax varies.
2.1.3.3: C++
Read section 12.3. Please note that the concept of classes is the same in different languages, though the syntax varies.