問題描述
耦合和內聚 (Coupling and cohesion)
我試圖將耦合和內聚的概念歸結為一個簡潔的定義。誰能給我一個簡短易懂的解釋（比維基百科上的定義短這裡和這裡）？它們是如何交互的？
謝謝。
有人有一個很好的簡短例子嗎？
參考解法
方法 1:
Coupling
Loose: You and the guy at the convenience store. You communicate through a well‑defined protocol to achieve your respective goals ‑ you pay money, he lets you walk out with the bag of Cheetos. Either one of you can be replaced without disrupting the system.
Tight: You and your wife.
Cohesion
Low: The convenience store. You go there for everything from gas to milk to ATM banking. Products and services have little in common, and the convenience of having them all in one place may not be enough to offset the resulting increase in cost and decrease in quality.
High: The cheese store. They sell cheese. Nothing else. Can't beat 'em when it comes to cheese though.
方法 2:
Coupling ‑ A measure of how much a module (package, class, method) relies on other modules. It is desirable to reduce coupling, or reduce the amount that a given module relies on the other modules of a system.
Cohesion ‑ A measure of how closely related the members (classes, methods, functionality within a method) of a module are to the other members of the same module. It is desirable to increase cohesion as that indicates that a module has a very specific task and does only that task.
方法 3:
Coupling means dependency on others.
Cohesion means completeness with itself.</p>
方法 4:
One of the best comprehensive discussions of software design concepts related to OO (including these ones) is Bertrand Meyer's Object Oriented Software Construction.
Regarding 'coupling', he gives his Weak Coupling / Small Interfaces rule as follows:
If two modules communicate, they should exchange as little information as possible.
Meyer's material related to cohesion isn't ever boiled down to a single pithy statement, but I think this sentence from Steve McConnell's Code Complete sums it up pretty well:
Cohesion refers to how closely all the routines in a class or all the code in a routine support a central purpose
方法 5:
A quick‑and‑dirty way to measure coupling is to measure your import (or similar) statements.
(by Jonathan、Shog9、Thomas Owens、Mansoor Mehmood、McKenzieG1、Hank Gay)