National Diploma Unit 4 Introduction to Software Development

1. National Diploma Unit 4Introduction to Software Development Documenting your programs

2. Program design • You should have analysed the user requirements and produced a specification • This is only the start of the design process – you might have to “return to the drawing board” many times before the program is finished

3. The Software Development Lifecycle • This is an idea used by software designers that the whole process can be thought of as a cycle • The stages are: • Analyse the problem • Produce a specification • Produce the program • Test it • Evaluate how well it met the original need

4. The Software Development Lifecycle • Can be a linear process • Start at one end and work to the other • A circularprocess • If it didn’t meet the original needs totally, go back to the start refining your original idea • This can also be thought of as a spiral • Hopefully, you will reach the end where no further refinement is needed

5. Documentation • This is the weak point for many programmers • It isn’t a good idea to do all design work on a computer • You wouldn’t start building a house without plans!

6. Documentation • Sketches can be used to show the user interface • The program flow can be shown by using Jackson Structure Diagrams or flowcharts • Code can be written in a general form called structured English or pseudocode • This can then be converted into any programming language

7. Documentation • Design happens in stages and your documentation should be broken down to show this • Using VB, many programmers start with the interface • They thencode the controls as needed • You still need to have an overall plan though

8. Flowcharts Start or End • Can be used to show program flow • Use standard symbols Disk storage A Process A decision (If…..Then) Manual input

9. Task • Prepare a flowchart for making beans on toast • Prepare a flowchart for a program that adds together two numbers

10. Jackson Structure Diagrams • These are diagrams that show the sub procedures that make up a whole program • Developed by one Michael Jackson (honestly) in the 1970s • They are “read” from left to right • Major processes are shown along the top • Elementary (the most broken down) sub processes are shown along the bottom

11. Assignment tasks • You will be required to produce several pieces of documentation: • A user manual • Technical documentation including specification, design diagrams, pseudocode, interface design plus actual screen images and code printouts

12. Jackson Structure Diagrams • Symbols are used in the box to show if it is an iteration (loop) process • Or a selection (If …Then) process • Ordinary sequential flow does not have an additional symbol • The handout has tasks to complete

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