1.7 CREATING TOP DOWN PROGRAMS
1. Define Objectives - Make a written description of what the program is expected to do.
2. Define Problem - Write out the relevant theory. This description should include variables, calculations and figures, which are necessary for a complete solution to the problem. From this we make a list of required data (inputs) and necessary results (output).
3. Design User Interface - The layout of the screen(s) must be done on paper. The method of data entry must also be considered. User options and help are also considered here. (There are numerous factors to be considered at this stage, as outlined in the course notes.)
4. Write Flow Program - This is the main code that decides when general operations occur. This is the most abstract part of the program, and is written calling dummy ‘program stubs’.
5. Expand Program - The dummy ‘stubs’ are now individually written as functions. These functions will call another set of dummy ‘program stubs’. This continues until all of the stubs are completed. After the completion of any new function, the program is compiled, tested and debugged.
6. Testing and Debugging- The program operation is tested, and checked to make sure that it meets the objectives. If any bugs are encountered, then the program is revised, and then retested.
7. Document - At this stage, the operation of the program is formally described. For Programmers, a top-down diagram can be drawn, and a written description of functions should also be given.
Golden Rule: If you are unsure how to proceed when writing a program, then work out the problem on paper, before you commit yourself to your programmed solution.
Note: Always consider the basic elements of Software Engineering, as outlined in the ES488 course notes.