SE 23: Coupling & Cohesion with Examples | Software Engineering

Summary

The transcript discusses software design concepts, focusing on the importance of cohesion and coupling in engineering. It explores various models like the teacher, student, and hood models, emphasizing their interdependencies and functions. The session delves into the significance of modularity, highlighting how it impacts software design and development. The speaker also touches on external coupling, control coupling, and the role of communication in software models. The discussion aims to provide insights into effective software design strategies that enhance maintainability, scalability, and reliability.

Takeaways

• 😀 The session focuses on the importance of software design, concepts, and engineering subject playlists.
• 🎓 It explores the next important topics, including session types, good and bad software, design coupling, and cohesion.
• 🔍 The discussion covers important questions that have been asked in previous sessions, emphasizing the need for understanding the relationship between software models.
• 🔗 It delves into the different types of models like teacher model, student model, hood model, and office model, and how they share information.
• 📊 The session explains the concept of dependency and the number of relationships between software models, using diagrams to illustrate total and four models.
• 🛠️ It introduces the idea of 'no dependency, no' in the second diagram, which is about model relationships and information sharing methods.
• 🔄 The concept of cardinality is discussed, which is about the degree of dependency and the number of relationships between software models.
• 💬 Communication between models is highlighted, emphasizing the need for models to work on input and output data, and the importance of updating records in databases.
• 🔢 The session also touches on the importance of logical cohesion, where elements of the model perform similar types of operations, such as error handling, sorting, searching, etc.
• 🔧 The benefits of high cohesion and low coupling in software design are discussed, including improved reliability, maintainability, and the ability to make changes with minimal impact on other models.

Q & A

What is coupling in the context of software design?

Coupling refers to the degree of interdependence or the number of relationships between different software modules. High coupling means modules are highly dependent on each other, while low coupling means they are independent.

What are the different types of coupling?

The types of coupling include no coupling, loose coupling, and strong coupling. No coupling means modules do not share any information, loose coupling means modules share minimal information, and strong coupling means modules heavily depend on each other.

What is cohesion in software design?

Cohesion refers to how closely related the responsibilities of a module are. High cohesion means that the module's elements are highly related and perform similar tasks, while low cohesion indicates that the module performs unrelated tasks.

Why is low coupling and high cohesion preferred in software design?

Low coupling and high cohesion are preferred because they improve readability, maintainability, and reusability of the software. Modules with low coupling and high cohesion are easier to understand, test, and modify without affecting other parts of the system.

Can you provide an example of global coupling?

An example of global coupling is when multiple modules in a program share and depend on a global variable. For instance, in a school management system, a global variable like 'teacherCount' might be shared across different modules.

What is external coupling?

External coupling occurs when two or more modules in a project depend on external tools, devices, or libraries. For example, if a module imports an external library for file handling or communication protocols, it is considered external coupling.

What is logical cohesion?

Logical cohesion occurs when elements within a module perform similar types of operations but may not be related in terms of functionality. For example, error handling, sorting, and searching operations grouped in one module demonstrate logical cohesion.

What is procedural cohesion?

Procedural cohesion refers to the elements of a module being related by the order in which tasks are performed. For instance, if a module contains functions that must be executed in a specific sequence, like reading data, processing it, and then saving it, this is procedural cohesion.

What is the difference between coincidental cohesion and functional cohesion?

Coincidental cohesion occurs when the elements within a module have no meaningful relationship, whereas functional cohesion happens when all the elements of a module contribute to a single, well-defined task or functionality. Functional cohesion is highly desirable in software design.

Why is high cohesion important in software design?

High cohesion is important because it ensures that the module's elements are related and work towards the same goal. This makes the system easier to maintain, understand, and test, and promotes code reuse.