Applying OOP Design Patterns in C++

#include <iostream>
#include <map>
#include <string>

class Employees {
private:
    std::map<int, std::string> employees; // private data member

public:
    void add_employee(int eid, const std::string& name) { // method to operate on private data
        employees[eid] = name;
    }

    void update_employee(int eid, const std::string& new_name) { // method to operate on private data
        if (employees.find(eid) != employees.end()) {
            employees[eid] = new_name;
        }
    }

    void display() const {
        for (const auto& employee : employees) {
            std::cout << "ID: " << employee.first << " Name: " << employee.second << std::endl;
        }
    }
};

int main() {
    Employees employees;
    employees.add_employee(1, "John");
    employees.add_employee(2, "Mark");

    employees.update_employee(2, "Jake");
    employees.display();
    // Outputs: 
    // ID: 1 Name: John
    // ID: 2 Name: Jake
    return 0;
}

#include <iostream>

class Vehicle {
protected:
    std::string color;
    std::string engine_type;
    bool engine_running;

public:
    Vehicle(const std::string& c, const std::string& e) : color(c), engine_type(e), engine_running(false) {}

    virtual void start_engine() = 0;
    virtual void stop_engine() = 0;
    virtual void drive() = 0;
};

class Car : public Vehicle {
public:
    Car(const std::string& c, const std::string& e) : Vehicle(c, e) {}

    void start_engine() override {
        engine_running = true;
        std::cout << "Car engine started!" << std::endl;
    }

    void stop_engine() override {
        engine_running = false;
        std::cout << "Car engine stopped!" << std::endl;
    }

    void drive() override {
        if (engine_running) {
            std::cout << "Car is driving!" << std::endl;
        } else {
            std::cout << "Start the engine first!" << std::endl;
        }
    }
};

int main() {
    Car car("red", "gasoline");
    car.start_engine();
    car.drive();

    return 0;
}