OOP&object-classes.cpp

#include <iostream>
#include <string>
using namespace std;

/*
  ===================================================================
  1. CORE CONCEPT: WHAT IS OOP? (Object-Oriented Programming)
  ===================================================================
  - OOP is a programming paradigm centered around "objects" that contain
    DATA (attributes) and FUNCTIONS (methods) operating on that data.
  - Advantages of OOP:
    1. Provides a clear structure for programs.
    2. DRY (Don't Repeat Yourself) principle -> Code is easy to maintain,
       reuse, and debug.
    3. Faster execution and shorter development time for full applications.
  
  - Procedural vs. OOP:
    * Procedural: Focuses on writing functions/procedures that act on data.
    * OOP       : Focuses on creating objects that combine both data and methods.

  ===================================================================
  2. CLASS vs. OBJECT
  ===================================================================
  - Class  : A user-defined data type that acts as a "blueprint" for objects.
  - Object : An instance of a class that inherits its attributes and methods.
             (e.g., Class: 'Car' | Objects: 'Volvo', 'Audi', 'Toyota')
*/

// ===================================================================
// 3. CREATING A CLASS
// ===================================================================
// Use the `class` keyword to define a class.
class Car {
  public:             // Access specifier: Members below are accessible from outside
    string brand;     // Attribute (variable inside a class)
    string model;     // Attribute
    int year;         // Attribute
}; // Don't forget to end the class definition with a semicolon (;)

class MyClass {
  public:
    int myNum;
    string myString;
};

// ===================================================================
// MAIN FUNCTION & CREATING OBJECTS
// ===================================================================
int main() {
    
    // --- Single Object Example ---
    cout << "=== 1. SINGLE OBJECT ===" << endl;
    
    MyClass myObj; // Create an object of MyClass
    
    // Access attributes using the dot syntax (.)
    myObj.myNum = 15;
    myObj.myString = "Some text";

    cout << "Number: " << myObj.myNum << endl;
    cout << "Text  : " << myObj.myString << endl;


    // --- Multiple Objects Example ---
    cout << "\n=== 2. MULTIPLE OBJECTS ===" << endl;
    
    // Object 1
    Car carObj1;
    carObj1.brand = "BMW";
    carObj1.model = "X5";
    carObj1.year = 1999;

    // Object 2 (Created from the same 'Car' class)
    Car carObj2;
    carObj2.brand = "Ford";
    carObj2.model = "Mustang";
    carObj2.year = 1969;

    // Output Object 1 values
    cout << carObj1.brand << " " << carObj1.model << " " << carObj1.year << endl;
    
    // Output Object 2 values
    cout << carObj2.brand << " " << carObj2.model << " " << carObj2.year << endl;

    return 0;
}