| Basic Unit | Objects (instances of classes) | Functions or procedures |
| Focus | Data and how it is manipulated (data-centric) | Procedures and sequence of tasks (process-centric) |
| Structure | Programs are organized around classes and objects | Programs are divided into functions |
| Data Handling | Data is encapsulated (private/protected) | Data is often global, accessible to all functions |
| Modularity | High, due to encapsulation and classes | Moderate, relies on function separation |
| Reusability | High, via inheritance and polymorphism | Limited, requires rewriting or copying code |
| Scalability | Scales well for large, complex systems | Becomes cumbersome in large systems |
| Security | Better, due to encapsulation and access control | Lower, as data is often exposed |
| Examples | Java, C++, Python (OO mode) | C, Fortran, Pascal |
| Real-World Modeling | Naturally models real-world entities (e.g., Car, Person) | Less intuitive for complex entities |
| Maintenance | Easier to modify and extend | Harder, as changes may affect multiple functions |