Cpp1_8.html

<article>
    <h1>C++ I: Page 8 - OOP: Classes & Objects</h1>

    <section>
        <h2>The Blueprint for Reality</h2>
        <p>Classes in C++ are the templates for creating objects, combining data (members) and functionality (methods) into a cohesive unit.</p>
        
        <h3>The Code implementation</h3>
        <pre><code class="language-cpp">/*
 * File: classes.cpp
 * Demonstration of class definition, constructors, const methods, and static members
 */
#include &lt;iostream&gt;
#include &lt;string&gt;

using namespace std;

class Vehicle {
private:
    string brand;
    int year;
    static int vehicleCount; // Static member: Shared by all instances

public:
    // 1. Constructor: Initialize with initializer list
    Vehicle(string b, int y) : brand(b), year(y) {
        vehicleCount++;
        cout << "Vehicle constructed: " << brand << endl;
    }

    // 2. Destructor
    ~Vehicle() {
        cout << "Vehicle destroyed." << endl;
    }

    // 3. Const Method: Cannot modify object members
    void displayInfo() const {
        cout << "Brand: " << brand << ", Year: " << year << endl;
    }

    // 4. Static Method: Belongs to class, not instance
    static int getVehicleCount() {
        return vehicleCount;
    }
};

// Initialize static member
int Vehicle::vehicleCount = 0;

int main() {
    // Stack instantiation
    Vehicle car("Toyota", 2020);
    car.displayInfo();
    
    // Heap instantiation (requires manual delete)
    Vehicle* truck = new Vehicle("Ford", 2022);
    truck->displayInfo();
    delete truck; // Critical to prevent memory leak
    
    cout << "Total vehicles: " << Vehicle::getVehicleCount() << endl;
    
    return 0;
}

/*
 * OOP Nuances:
 * 1. Initializer lists (e.g., : brand(b)) are faster than assignment in body.
 * 2. 'const' method: Ensures the method doesn't modify object members,
 *    essential for const objects.
 * 3. Static members: Shared across all instances of a class.
 * 4. Access Modifiers: 'private' protects internal state, 'public' exposes interface.
 * 5. Destructors: Automatic clean up for stack objects, manual for heap objects.
 * 6. Always initialize your members; undefined state can lead to bugs.
 */
        </code></pre>
        <div class="interactive-sim">
            <h3>Object Creation Simulator</h3>
            <button class="sim-button" onclick="
                const out = document.getElementById('sim-output-cpp1_8');
                out.innerHTML = 'Vehicle car(&quot;Toyota&quot;, 2020);<br>';
                setTimeout(() => out.innerHTML += '>> Car instance created!', 800);
            ">Run Simulation</button>
            <div id="sim-output-cpp1_8" class="sim-output"></div>
        </div>
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