Data coupling Data coupling occurs when modules share data through, for example, parameters. In this situation, a modification in a field that a module does not need may lead to changing the way the module reads the record. Stamp coupling (data-structured coupling) Stamp coupling occurs when modules share a composite data structure and use only parts of it, possibly different parts (e.g., passing a whole record to a function that needs only one field of it). ![]() Control coupling Control coupling is one module controlling the flow of another, by passing it information on what to do (e.g., passing a what-to-do flag). ![]() This is basically related to the communication to external tools and devices. External coupling External coupling occurs when two modules share an externally imposed data format, communication protocol, or device interface. ![]() But it can lead to uncontrolled error propagation and unforeseen side-effects when changes are made. Common coupling Common coupling is said to occur when several modules have access to the same global data. This violates information hiding - a basic design concept. ![]() Content coupling (high) Content coupling is said to occur when one module uses the code of other module, for instance a branch. a set of one or more statements having a name and preferably its own set of variable names. A module here refers to a subroutine of any kind, i.e.
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