模块的耦合与内聚（Coupling and cohesion of modules）.docVIP

模块的耦合与内聚（Coupling and cohesion of modules） Coupling and cohesion of modules Coupling (Coupling) is a measure of the degree of dependence between modules. Cohesion and coupling are closely related. Modules that are strongly coupled with other modules usually imply weak cohesion, while strongly cohesive modules usually imply weak coupling with other modules. The module design pursues strong cohesion and weak coupling. Cohesion (Cohesion) is a measure of the degree of correlation between components within a module. Coupling (Coupling) Coupling (Coupling) refers to the existence of close cooperation and mutual influence between the input and output of two or more than two of the circuit elements or the electrical network, and through the interaction from one side to another energy transfer phenomenon; sum up coupling refers to two entities of a measure of mutual depend on each other for. The following: Non direct coupling: there is no direct relationship between the two modules, and the connection between them is achieved entirely through the control and invocation of the main module Data coupling: when one module accesses another module, each other exchanges input and output information through simple data parameters (not control parameters, public data structures or external variables). Tag coupling: a set of modules that pass the record information through the parameter table, that is, tag coupling. This record is a substructure of a data structure, not a simple variable. Control coupling: if a module passes control information such as switch, flag, name and so on, it obviously controls the function of selecting another module, that is, control coupling. External coupling: a group of modules accesses the same global simple variable, not the same global data structure, and does not pass the global variable information through the parameter table, which is called external coupling. Public coupling: if a set of modules accesses the same common data environment, the coup