C module | a special-purpose function such as the user interface for a particular system | side effects if it does not modify any data, and does not leave behind any information, other than its result, that would have an effect on other computations | module | reusable if it can be used in several different systems with little or no modification | 9.1 - The Process of Design | if related aspects of a system are kept together in this module, and unrelated aspects are kept out |
C file | a special-purpose function such as the user interface for a particular system | side effects if it does not modify any data, and does not leave behind any information, other than its result, that would have an effect on other computations | file | reusable if it can be used in several different systems with little or no modification | 9.1 - The Process of Design | if related aspects of a system are kept together in this module, and unrelated aspects are kept out |