Coupling and cohesion are methods to measure the relationship between and within modules.

Coupling And Cohesion In Software Engineering Ppt Project
Coupling And Cohesion

A software system is divided into multiple modules, where each and every module are capable of performing a function independently. This technique is known as Modularization.

Further, Coupling and Cohesion indicate to which degree a module can carry out a task on its own and the strength of elements related to one other within that respective module.

Coupling measures interaction between modules whereas Cohesion focuses on interaction within a module.

Difference between Coupling and Cohesion in Tabular form

Coupling	Cohesion
It refers to relationship between two or more modules	It refers to relationship between two or more elements within a module
It focuses on measuring a module's dependency with other modules	It focuses on measuring a module's functional strength
It is ideal to have low coupled modules which states dependency between modules	It is ideal to have a module with high cohesiveness which states implementation of a particular feature with low or no communication with other module
It is based on communication between two modules. Therefore, it is known as inter-module concept	It is based on communication between two elements or fields within a single module. Therefore, it is known as intra-module concept
There are 6 types of coupling: Data Coupling,Stamp Coupling,Control Coupling,External Coupling,Common Coupling and Content Coupling	There are 8 types of cohesion: Functional Cohesion,Sequential Cohesion,Communicational Cohesion,Procedural Cohesion,Temporal Cohesion,Logical Cohesion and Coincidental Cohesion
It is not possible to achieve no coupling among all modules	It is possible to achieve full cohesive modules

In software, we already know the concepts of cohesion and coupling affect structural complexity - from past studies, we want: - high cohesion and - low coupling Using Wood’s Task Complexity Model to Aid in Studying Structural complexity Has 3 essential concepts: Products: things created by acts and behaviors Acts: pattern of behavior that.
Coupling and Cohesion. I believe the source of the terms Coupling and Cohesion is from a paper called, Structured Software Design (1974), Wayne Stevens, Glenford Myers, and Larry Constantine. This paper discusses characteristics of 'good' programming practices that can reduce maintenance and modification costs for software. Loose (Low) coupling.

Informational Cohesion. Informational cohesion describes a module as performing a number of actions, each with a unique entry point, independent code for each action, and all operations are performed on the same data. – In informational cohesion, each function in a module can perform exactly one action.

Coupling

The measure of how a module depends on other modules is known as coupling.

It can be viewed as highly coupled, loosely coupled and uncoupled. These are based on their degree of dependencies.

Uncoupled signifies no dependencies at all, all the modules or methods have nothing to do with other modules. No communication between this type of coupling takes place.

Highly coupled refers to the high dependency of the module with each other.

Loosely coupled represents less dependency which means that only essential piece of code would depend and communicate with each other. It means undesired data would not be passed to another section of code.

In programming, the ideal way of having a program to be loosely coupled is by using the concept of interfaces.

Coupling can be classified based on certain characteristics:

Cohesion

It represents how a module’s attributes or fields are functionally related together. A module that is highly cohesive, has little or no interaction with other modules.

Therefore, it is better to have maximised cohesive modules where elements within a module interact properly to one another.

A module with high cohesion represents that it is strongly capable of performing a particular functionality or task, considering less or no communication with other modules.

Cohesion can be classified based on certain characteristics:

A Good Relationship between Cohesion and Coupling

A software with less coupled and high cohesive module design should always be preferred. A software design breaks down into multiple modules where each module solves a particular problem.

These modules are structured in a proper hierarchy. Apple mac free download. Each and every module must be implemented in a way that they are having less dependency with other modules and the elements within that module should be functionally related together.

Coupling And Cohesion In Software Engineering Ppt Project

Cohesion: Cohesion can be defined as the degree of the closeness of the relationship between its components. In general, it measures the relationship strength between the pieces of functionality within a given module in the software programming. It is an ordinal type of measurement, which is described as low cohesion or high cohesion.

In a good module, the various parts having high cohesion is preferable due to its association with many desirable traits of the software such as reliability, re-usability, robustness and understand-ability.

On the other hand, a low cohesion is associated with the undesirable traits, including difficulty in maintaining, reusing and understanding. If the functionalities embedded in a class have much in common, then the cohesion will be increased in a system.

High cohesion leads to the increased module re-usability because the developers of the application will easily find the component they look for in the cohesive set of operations offered by the module.

The system maintainability will be increased due to logical changes in the domain effecting fewer modules.The module complexity also reduces, when there is a high cohesion in the programming.

i. Coincidental cohesion: the parts of a component are not related but simply bundled into a single component. Harder to understand and not reusable.

ii. Logical association: similar functions such as input, error handling, etc. put together. Functions fall in same logical class. May pass a flag to determine which ones executed. Interface difficult to understand. Code for more than one function may be intertwined, leading to severe maintenance problems. Difficult to reuse

iii. Temporal cohesion: Crossfire wargame rules. all of statements activated at a single time, such as start up or shut down, are brought together. Initialization, clean up. Functions weakly related to one another, but more strongly related to functions in other modules so may need to change lots of modules when do maintenance.

Coupling And Cohesion

iv. Procedural cohesion: a single control sequence, e.g., a loop or sequence of decision statements. Often cuts across functional lines. May contain only part of a complete function or parts of several functions. Functions still weakly connected, and again unlikely to be reusable in another product.

v. Communicational cohesion: operate on same input data or produce same output data. May be performing more than one function. Generally acceptable if alternate structures with higher cohesion cannot be easily identified. Still problems with reusability.

vi. Sequential cohesion: output from one part serves as input for another part. May contain several functions or parts of different functions.

vii. Informational cohesion: performs a number of functions, each with its own entry point, with independent code for each function, all performed on same data structure. Different than logical cohesion because functions not intertwined.