How is structured design different from object oriented design

Each of these functions performs a subtask. Usually, as each function represents a specific functionality, it is easier for the programmer to test and debug the code, but this can differ depending on the program. C language and Pascal are two common structured programming languages.

In the structured programming C, the user can create his own user-defined functions. The main function calls the other functions. It indicates the execution of the program. When there is a function call , the control is passed to that function. After completing the function, the control passes back to the main program. Moreover, a variable inside a function is a local variable, and global variables are accessible by all the functions.

Object oriented programming allows the programmer to represent real-world scenarios using objects. An object is any entity that has states and behaviours. It can further define a use-case and make use-case modeling much easier.

Application development moves from custom development to assembly of pre-built, pre-tested, reusable software components that operate with each other. A CBD developer can assemble components to construct a complete software system. RAD is a set of tools and techniques that can be used to build an application faster than typically possible with traditional methods.

It does not replace SDLC but complements it, since it focuses more on process description and can be combined perfectly with the object oriented approach. Its task is to build the application quickly and incrementally implement the user requirements design through tools such as visual basic, power builder, etc.

Software development and all of its activities including testing are an iterative process. Therefore, it can be a costly affair if we wait to test a product only after its complete development. Here incremental testing comes into picture wherein the product is tested during various stages of its development. Object Oriented Approach Advertisements. Previous Page. Next Page. Previous Page Print Page. Save Close. Dashboard Logout. Skip to content.

Change Language. Related Articles. Table of Contents. Save Article. Improve Article. Similarly, in object-oriented design, there are four key steps to be performed 6i :.

The first step involves analyzing life cycle of each object and formalizing the life cycle in an object state diagram. Next, class relationships are defined in a class diagram.

Each service that is provided by a class is defined including any logic that is necessary. Finally, the class and object diagrams are completed along with all class templates 8. Object-Oriented Analysis vs. Traditional Methods. Before the introduction of Object Oriented Analysis and Design, most Information Systems professionals were taught that the classical waterfall development life cycle was the proper way to approach software engineering and that "top level decomposition of processes was a practical way of handling large software development projects" 8.

These traditional methods built the foundation of modern software practices, and yet this foundation is being shaken by object oriented analysis and design. Structured systems development began in the s with the concept of systems development life cycle. In the s, process-oriented structured methodologies were developed to promote a more effective analysis and design technique 9i. In the s, planning and modeling of data began to play a more important role in development, resulting in data-oriented methodologies such as information engineering.

Organizations continue to use traditional methods of software development, but they are coming to realize that these methods have shortcomings that include the following:. These shortcomings have prompted developers to examine different ways of thinking about approaches to systems development.

Object-oriented systems development is in the forefront of this shift in thinking. Top-down structured design approaches development as a simple matter of algorithmic decomposition, where each module in a system denotes a major step in some overall process. In contrast, object-oriented decomposition is based on objects and not algorithms. Object-oriented analysis strives to describe what the system should do in terms of key objects in the problem domain while object oriented design strives to describe how the system will work using these objects.

OOA differs the most from Structured analysis. Information engineering is closer to OOA because it provides a variety of tools for modeling of entities namely, entity-relationship diagramming.

Developers who are currently using structured analysis techniques usually discover that their experience in modeling requirements using data flow diagrams is irrelevant or worthwhile only in the context of modeling existing procedures. Those developers schooled in information engineering will find the road to object-oriented analysis much easier to follow. However, developers still need to alter their views from modeling disembodied processes to encapsulated services 8.

Object Oriented design is completely contrary to both structured methodologies and information engineering.