It means undesired data would not be passed to other section of code.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. Therefore, it is known as inter-module concept It is based on communication between two elements or fields within a single module. Difference Between Coupling And Cohesion In Software Engineering Ppt Software Design BreaksA software design breaks down into multiple modules where each module solves a particular problem. 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. As any changes ripple through connected code, refactoring of highly coupled code is difficult. Functional correctness reigns supreme, but if we put that aside what should we look at next Cohesion and coupling are the two most significant aspects of code impacting software quality. A set of functions, an interface, is considered cohesive when each function is closely related to another. For example, logerror and logwarning are closely related and belong nicely together in a single log module. As functions diverge in their behaviour a module becomes less cohesive. ![]() Short and precise sentences are preferred to longer, verbose, and generic ones. Contrast The log module records diagnostic messages to This module records diagnostic messages and parses json. If we cant give a module a name theres a good chance it lacks cohesion. A module that provides an assortment of calculations doesnt sound as cohesive as a module that provides bond amortization and valuation. While looking at the code, or interface, we can keep a single unifying theme in our head. As all functions relate to that theme it is easier to understand the code, and thus easier to extend the code, debug errors, or simply use the interface. ![]() Once weve learned the basic types used in a module it is not far easier to use the rest of the module. Since all the functions are related, it makes sense well have to replace all of them to swap out the module. Similarly writing a mock object for testing becomes more straight forward. If there are too many unrelated functions in the interface we find our unit tests also lose focus. Tightly coupled modules rely extensively on the specific state of each other, sharing variables and many types. Loosely coupled modules are fairly independent: they have a few well defined APIs and share a limited amount of, or no data. A module that has a high ratio of public information compared to private information will result in tight coupling. A module that exposes a minimal interface will result in loose coupling. Difference Between Coupling And Cohesion In Software Engineering Ppt Series Of ModulesSay we have a series of modules, where each depends on each other in turn: A - B - C. ![]() Independent code is great for readability since we can make sense of it in isolation. This also means it is harder to write tests for them since it is unclear where one module ends and another begins.
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