Cohesion & Coupling

Jagnesh Chawla(jagneshchawla@gmail.com)

Presentation Of

Software engineering

Topic : Cohesion & Coupling

Jagnesh Chawla(jagneshchawla@gmail.com)

Contents :Coupling Highly Coupled Loosely Coupled Uncoupled Types Of Coupling CohesionTypes Of Cohesion

Jagnesh Chawla(jagneshchawla@gmail.com)

Coupling Coupling is measure of the

independence of components. Coupling is related to cohesion.It is an indication the strength of

inter connections between the components in a design .

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Highly coupled

These types of systems have interconnections , with program units dependent on each other.

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Highly coupled:

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Loosely coupled

Loosely coupled systems are made up of components which are independent or almost independent.

In this less dependences are available.

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Loosely coupled:

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Uncoupled

Uncoupled components have interconnections at all.

No Dependencies

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Uncoupled:

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The range of coupling measures:

Content

coupling

Common

coupling

Control

coupling

Stamp coupling

Data coupling

Uncoupled

Low

Loose

High coupling

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Content coupling:When one component actually

modifies another .Then the modified component is

completely dependent on the modifying one.

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Common coupling:We can reduce the amount of

coupling somewhat by organizing our design so that data are accessible from a common data store.

ComponentX

Change V1

To zero

ComponentY

Increment V1

ComponentZ

V =V2+A

Global:A1A2A3Variables:V1V2

T T

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Control coupling:When one component passes

parameters to control the activity of another component.

We say that there is control coupling between the two.

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Stamp coupling:

When data structure is used to pass information from one component to another.

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Data coupling:

If only data are passed, the components are connected by data coupling.

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Cohesion:

The cohesion of a component is a measure of the closeness of the relationship between its components.

Jagnesh Chawla(jagneshchawla@gmail.com)

Coincidental:

The worst degree of cohesion, coincidental is found in a component whose parts are unrelated to one another.

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Logical cohesion:

It is the next higher level of cohesion , where several logically related functions or data elements are placed in same component.

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Temporal cohesion:

Sometime a component is used to initialize a system or a set variables.

Such a component performs several functions in sequence ,but the functions are related by the timing involved, so its cohesion is temporal.

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Procedurally cohesion:

When function are grouped together in a component just to ensure this order the component is procedurally cohesive.

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Communicationally:

Communicationally cohesion often destroys the modularity and functional independence of the design.

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Sequential cohesion:

If the output from one part of a component is input to the next part the component has sequential cohesion.

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Thank you ……