Jackson Structured Diagrams Programming Concepts Jackson Structured Diagrams

Jackson Structured Diagrams This is a useful way of representing the structure of a program, when a program is large and complex, it is important to plan out the solution before attempting to write any program code. By using a Jackson structured diagram your system can be documented and given to a programmer to aid the development of the program.

Jackson Structured Diagrams The basic structure to a JSD is as follows: It resembles a family tree, with the main modules being written across the top line. You read it from left to right completing any sub branches before being able to move on to the next module. JSD structures programs and data in terms of sequences, iterations and selections. Program Jackson Initialise InputAndProcess Output

Jackson Structured Diagrams Example - Loop b = 10 Do While (a<b) a = a + 1 Loop To represent a Loop using JSD: Calculate result* Initialise InputAndProcess Output Do While (a<b)

Jackson Structured Diagrams Example - Selection To represent Selection using JSD: Check if A >B If (A>B) Then Msgbox (“A is > B”) True Msgbox (“B is > A”) False

Jackson Structured Diagrams JSD is a structured analysis and design method similar to SSADM. It uses Entity Structure Diagrams (ESD) and Network Diagrams (ND) to model a system.