Difference between Function Oriented Design and Object Oriented Design

Last Updated : 03 Jan, 2025

Function-oriented design focuses on defining and organizing functions to perform specific tasks, starting with a high-level description and refining it step-by-step. It uses a top-down approach and often relies on structured analysis and data flow diagrams. On the other hand, object-oriented design emphasizes the data to be manipulated, organizing the software around objects that combine data and behavior. This approach uses a bottom-up strategy, beginning with identifying objects and classes, and often employs UML for design.

What is Function Oriented Design?

Function-oriented design is the result of focusing attention on the function of the program. This is based on the stepwise refinement. Stepwise refinement is based on the iterative procedural decomposition. Stepwise refinement is a top-down strategy where a program is refined as a hierarchy of increasing levels of detail.

We start with a high-level description of what the program does. Then, in each step, we take one part of our high-level description and refine it. Refinement is actually a process of elaboration. The process should proceed from a highly conceptual model to lower-level details. The refinement of each module is done until we reach the statement level of our programming language.

What is Object Oriented Design?

Object-oriented design is the result of focusing attention not on the function performed by the program, but instead on the data that are to be manipulated by the program. Thus, it is orthogonal to function-oriented design. The object-oriented design begins with an examination of real-world "things". These things have individual characteristics in terms of their attributes and behaviors.

Objects are independent entities that may readily be changed because all state and representation information is held within the object itself. Objects may be distributed and may execute sequentially or in parallel. Object-oriented technology contains the following three keywords -

Objects: Software packages are designed and developed to correspond with real-world entities that contain all the data and services to function as their associated entity messages.
Communication: Communication mechanisms are established that provide how objects work together.
Methods: Methods are services that objects perform to satisfy the functional requirements of the problem domain. Objects request services of the other objects through messages.

Difference Between Function Oriented Design and Object Oriented Design

COMPARISON FACTORS	FUNCTION ORIENTED DESIGN	OBJECT ORIENTED DESIGN
Abstraction	The basic abstractions, which are given to the user, are real world functions.	The basic abstractions are not the real world functions but are the data abstraction where the real world entities are represented.
Function	Functions are grouped together by which a higher level function is obtained.	Function are grouped together on the basis of the data they operate since the classes are associated with their methods.
execute	carried out using structured analysis and structured design i.e, data flow diagram	Carried out using UML
State information	In this approach the state information is often represented in a centralized shared memory.	In this approach the state information is not represented in a centralized memory but is implemented or distributed among the objects of the system.
Approach	It is a top down approach.	It is a bottom up approach.
Begins basis	Begins by considering the use case diagrams and the scenarios.	Begins by identifying objects and classes.
Decompose	In function oriented design we decompose in function/procedure level.	We decompose in class level.
Use	This approach is mainly used for computation sensitive application.	This approach is mainly used for evolving system which mimics a business or business case.