feat: added food delivey system

[adityacosmos24]

Add a Food Delivery System using C++ and OOP Design Patterns

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✅ Summary

This PR implements the complete Food Delivery System in C++ following Object-Oriented Design Principles and key Design Patterns — Singleton, Factory, and Strategy.
The system simulates a simplified food ordering platform similar to Zomato, where users can browse restaurants, select items, place orders (delivery or pickup), and pay using multiple payment methods.

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🧩 Key Features Implemented

📦 Models

• User, Restaurant, MenuItem, Cart, Order, PickupOrder, DeliveryOrder

🏢 Managers (Singletons)

• RestaurantManager – handles restaurant data and menus
• OrderManager – manages active and past orders

🏭 Factories (Factory Pattern)

• OrderFactory (abstract interface)
• NowOrderFactory and ScheduledOrderFactory for creating order types dynamically

💳 Payment Strategies (Strategy Pattern)

• PaymentStrategy (interface)
• Implementations: CreditCardPaymentStrategy, UpiPaymentStrategy, NetbankingPaymentStrategy

🛎️ Services

• NotificationService for sending notifications after order placement

🧰 Utils

• TimeUtils for timestamps and order scheduling

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🧠 Design Highlights

• Demonstrates SOLID principles and design pattern usage for modularity and scalability.

• Clean folder structure aligning with UML design:

  Food_Delivery_System/
  ├── models/
  ├── managers/
  ├── factories/
  ├── strategies/
  ├── services/
  └── utils/
  

• Code documented with comments explaining relationships and responsibilities.

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🧪 Testing

• Verified all modules interact correctly through a main driver file.
• Tested order creation (pickup and delivery), cart management, and all payment strategies.

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📸 Attachments

• UML Diagram (for reference)
• Example Console Output Screenshot

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📜 Additional Notes

• Code written in C++17.
• Follows consistent naming conventions and modular structure.

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Requesting Review
Please review the code structure, design implementation, and adherence to OOP principles.
Feedback on design extensibility and naming conventions is welcome.