Lesson 9

This module discussed the fundamental concepts of structured programming. You now have the skills and knowledge necessary to:

1. Describe structured programming
2. Identify disadvantages of unstructured programs
3. Describe and use pseudocode
4. Describe the three control flow constructs of structured programming
5. Identify advantages of using subprograms

Question: What do subprograms do and how do subprograms help the main program?
Answer: They do anything that the main program can do. They help you organize your total program (main program and subprograms) by grouping specific tasks in a well defined location. They can save you repeating similar program structures at several places in your code. Also, for many tasks someone has already written a subprogram to do the job and you save a lot of work by picking up their subprogram and plugging it into your work. You will see an example of this when we start solving systems of linear equations (say 10 equations and 10 unknowns).
You will define the equations, then let somebody else's subprogram solve them. In the next module you will begin putting theory into practice by writing and running your first program.