C++ OOP Fundamentals: Objects, Classes, Inheritance, and Polymorphism

#include <iostream>
#include <string>
#include <vector>
#include <memory>

// Abstraction & Polymorphism Base
class Vehicle {
protected:
    std::string brand;
    int maxSpeed;
public:
    Vehicle(std::string b, int speed) : brand(std::move(b)), maxSpeed(speed) {}
    virtual ~Vehicle() = default; // Essential virtual destructor
    virtual void drive() const = 0; // Pure virtual function
};

// Inheritance & Encapsulation
class ElectricCar : public Vehicle {
private:
    int batteryCapacity;
public:
    ElectricCar(std::string b, int speed, int battery)
        : Vehicle(std::move(b), speed), batteryCapacity(battery) {}

    void drive() const override {
        std::cout << "[ElectricCar] Driving " << brand << " silently at " 
                  << maxSpeed << " km/h with " << batteryCapacity << " kWh battery.\n";
    }
};

int main() {
    std::vector<std::unique_ptr<Vehicle>> garage;
    garage.push_back(std::make_unique<ElectricCar>("Tesla Model S", 250, 100));
    garage.push_back(std::make_unique<ElectricCar>("Porsche Taycan", 260, 93));

    for (const auto& vehicle : garage) {
        vehicle->drive();
    }
    return 0;
}