
Appendix: Solutions to Selected Exercises ◾ 549
17. Coupling is a property of pairs of modules, while cohesion is a prop-
erty of individual modules. Coupling between modules is the extent
of interdependence between modules, whereas cohesion of a module
is the extent to which the elements of the module have a common
purpose, that is, are part of the same function.
It is generally believed that if a design is made up of a number of
related modules, then there should be (as far as possible) a low level of
coupling; this way, errors made in any one module should aect a min-
imum number of others. Also, low coupling should help keep inde ...