Structure Charts

Graphical representation of the logic of the program, the decisions made, where they are made, the alternative paths, the data stores, and the inputs and outputs that make up the system Graphical representation of the structure of the program, the hierarchy of the modules, the calls that are made to each of the modules, the flags that are sent between modules. Text representation that incorporates the logic and the structure of the program. Uses Control structures, variables, flags, subprograms. Different Models, Different Purposes

Structure Charts The Structure Chart is like a site map They describe the functions and subfunctions of each part of system They show the relationships between the modules of a program; the parent/child relationship and how they “talk” to each other. They show simple and direct organisation Each module performs a specific function Each layer in a program performs specific activities It is tree-like with root module and branches Your read the Components from top to bottom, left to right They are helpful because they emphasise structure and reusability

A Simple Structure Chart for the Calculate Pay Amounts Module Systems Analysis and Design in a Changing World, 3rd Edition

Structure Chart for Entire Payroll Program Systems Analysis and Design in a Changing World, 3rd Edition Each module performs a specific function Each layer performs specific activities

Sample System Flowchart - Payroll System Systems Analysis and Design in a Changing World, 3rd Edition

Developing a Structure Chart Module Analysis Use other models like the system flowchart, DFD and IPO Diagrams to help you identify the modules You typically develop the Upper-level modules first, then step- wise refinement of the lower-level modules Use your DFDs to find processes that represent the most fundamental changes from input to output You need to ensure you include every function that you need to construct for the actual software solution “Calling” Analysis Use your DFD diagram to identify data that goes into and out of different modules Use your IPO Diagrams to identify data inputs and data output. Use your algorithm for repetition and decisions, and to identify possible flags and temporary data.

High-level Structure Chart for the Customer Order Program Systems Analysis and Design in a Changing World, 3rd Edition

Developing the Modules for the Structure Chart Systems Analysis and Design in a Changing World, 3rd Edition Qs: What is the output/s? What are the inputs? What are the processes? Customer Order ProcessConfirm

Developing the Modules for the Structure Chart Systems Analysis and Design in a Changing World, 3rd Edition The Parent/Boss Module The Child/Worker Modules

Adding the “call” information Systems Analysis and Design in a Changing World, 3rd Edition Q: What information is passed between modules? Q: What modules are iterative? What flags are required?

Adding the “call” information Systems Analysis and Design in a Changing World, 3rd Edition

The Structure Chart for the Create New Order Program Systems Analysis and Design in a Changing World, 3rd Edition

The Ideal Structure Chart High-quality structure charts result in programs that are modular, reusable, and easy to implement. Ideal modules should perform only one task. Communication between modules should be kept to the minimum required to be passed in and out of a module

Additional

Top-down Modular Design This is our initial problem Look_Up_Date

Structure Chart - Level 1 Look_Up_Date Break the problem down into subproblems Initialisation Get_Input Calculate_Date Output_Date

Structure Chart - Level 2 Look_Up_Date Calculate_DateGet_InputInitialisationOutput_Date Input Starting Date Further break down if necesary Input number of days

Structure Chart - Level 3 Modulisation Done! Look_Up_Date Input Starting Date Calculate_DateGet_InputInitialisation Input Number of Days Output_Date

Structure Chart - Level 4 Now for the data passing Look_Up_Date Input Starting Date Calculate_DateGet_InputInitialisation Input Number of Days Output_Date Start dateNr Days Start date Date Nr Days Initialised

Another Structure Chart