Page 213 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Unit 10: Coding Standards

Problem 2 Notes
Turn on a light bulb
Sub-problem 1: locate bulb (one task, one action)

Sub-problem 2: depress switch

Given a list of students’ test scores, find the highest and lowest score and the average score.
Sub-problem 1: read students’ scores
Sub-problem 2: find highest score
Sub-problem 3: find lowest score

Sub-problem 1 can be considered as one action and therefore wants no further refinement. Sub
problems 2 and 3 however can be further divided into a group of actions. This is left as an
exercise for the student.
Advantages of the Top-Down Design Method
• It is easier to comprehend the solution of a smaller and less complicated problem than to
grasp the solution of a large and complex problem.
• It is easier to test segments of solutions, rather than the entire solution at once. This method
allows one to test the solution of each sub-problem separately until the entire solution has
been tested.
• It is often possible to simplify the logical steps of each sub-problem, so that when taken
as a whole, the entire solution has less complex logic and hence easier to develop.

• A simplified solution takes less time to develop and will be more readable.
• The program will be easier to maintain.
A partial formalization of the concept of algorithm began with attempts to
solve the Entscheidungsproblem (the “decision problem”) posed by David
Hilbert in 1928.

Self Assessment Questions
1. ................. errors are very difficult to find as they do not manifest easily.

(a) Software (b) Synchronization
(c) String handling (d) Warning
2. An .......................is a sequence of precise instructions for solving a problem in a finite
amount of time.
(a) syntax (b) program
(c) algorithm (d) none of these

3. Advantages of the top-down design method:
(a) The program will be easier to maintain
(b) It must be precise and unambiguous

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