Functional Decomposition

Introduction

• There are a variety of paradigms available for managing the complexity of a program.
• An object oriented paradigm attempts to encapsulate actions and attributes within familiar objects. You talk about the design in terms of objects and their common activities and operations, and common diagrams include object hierarchy diagrams, object interaction diagrams, and sequence diagrams.
• Functional decomposition is another (simpler but less powerfull) paradigm where the program is broken down into a series of defined steps, and these steps are seperated into seperate modules. You talk about the design in terms of functions and subroutines. Common diagrams are flowcharts.
• Perl's functional decomposition tool is the subroutine, also known as a function.
• To declare a function, use the following form:
  

sub  subroutine_name  {
     statement; 
     statement; 
     statement; 
}