Machine Coding (OOP)
Machine Coding — OOP Design Problems
Section titled “Machine Coding — OOP Design Problems”Introduction
Section titled “Introduction”Machine coding rounds test your ability to design and implement OOP systems. You’re given a problem and expected to create a clean, extensible class design with proper OOP principles.
General Approach
Section titled “General Approach”- Understand Requirements — What are the core features?
- Identify Key Entities — Nouns = potential classes
- Define Relationships — IS-A (inheritance), HAS-A (composition/aggregation)
- Create Class Diagram — Properties, Methods, Relationships
- Write Code — Implement with proper OOP principles
- Test with Scenarios — Verify main use cases
Example: Parking Lot System
Section titled “Example: Parking Lot System”Key Classes
Section titled “Key Classes”ParkingLot— Manages floors and ticketsParkingFloor— Contains parking spotsParkingSpot— Individual spot (Small/Medium/Large)Vehicle— Bike, Car, TruckTicket— Records entry/exit and calculates fee
Example: ATM Machine
Section titled “Example: ATM Machine”Key Classes
Section titled “Key Classes”ATM— Machine with card reader and cash dispenserBankAccount— Encapsulated balanceSession— Tracks authenticationTransaction— Records operations
Tips for Machine Coding
Section titled “Tips for Machine Coding”| Tip | Description |
|---|---|
| Start with entities | Identify nouns as potential classes |
| Define relationships | IS-A, HAS-A associations |
| Use encapsulation | Private fields, public methods |
| Think extensibility | Can you add new types without modifying core? |
| Handle errors | Invalid inputs, edge cases |
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