Modules Programmers break programming problems down into smaller, reasonable units called modules, subroutines, procedures, functions, or methods When you create a module or subroutine, you give the module a name that a calling program uses when the module is about to execute A module can call other modules Functions are a type of module

Creating Hierarchy Charts A hierarchy chart illustrates module relationships Does not tell you what tasks are to be performed within a module and thus does not show control flow. Does not tell you when or how a module executes Rather, identifies which routines exist within a program and which routines call which other routines A hierarchy chart shows hierarchy, that is, subordinate-superordinate relationships. In particular, it shows which modules (functions) call which others.

Creating Hierarchy Charts (continued)

Numbering of Modules

Module Listing Order 0 1 2 2.1 2.2 2.3 2.1.1 2.1.2 2.1.2.1 2.1.2.2