The Art of Programming Top-Down Design

The Art of Problem Solving The art of problem solving is the transformation of an English description of a problem into a form that permits a mechanical solution. A straightforward example of this process is transforming an algebra word problem into a set of algebraic equations that can then be solved for the unknowns.

Software Development Method Requirements specification Analysis Design Implementation or coding Testing

Requirements Specification State the problem and gain a clear understanding of what is required for the solution. –Sounds easy but can be most difficult part –Must define the problem precisely eliminate unimportant aspects zero in on root problem

Analysis Identify input and outputs –What information should the solution provide? –What data do I have to work with? Identify data types needed

Design Develop a list of steps to solve the problem. This is called an algorithm. –First list the major steps of the problem that need to be solved (subproblems) –Now attack each of the subproblems. This is called refining the algorithm. (this process is like divide and conquer)

Implementation or Coding Notice that until now the steps are the same regardless of the programming language you are using. Translate your algorithm from pseudocode to Pascal. –Good programming style –comments

Testing Test the completed program and verify it works as expected. Don’t rely on just one test case. Run the program using several different sets of data. Try to trick the program. A well written program should handle any error a user may make.

Midterm #1 Chapters 1 (not really), 2 (not really), 3, 4, 5 February 24, 2000 (two weeks from today) I expect to finish chapter 5 on February 17 February 22 will be a review (there is a chance we will have 1 or 2 topics to finish from chapter 5 that day)