Lecture 9. AMES 5, Tues.2 Feb. 1999

From the course outline we see the reading assignment this week is Chapter 6 on Finding and Correcting Errors.

You need to turn in modified versions of all the example programs in this chapter, and do Practice Programs 6.1 and 6.2. The "do trace" debugging routine for True Basic is discussed, along with other techniques for finding errors. For PP6.1, test using "do trace, step (noerror$,x1,x2,a,b,c,extype,extext$)" in the command window (type control J to open, and paste in the copied command).

Some of the methods presented include:

• Playing computer...reading through a computer program as though you were the machine.
• Temporary PRINT statements.
• The DO TRACE command.
• The BREAKPOINT command.
• Calculation errors.
• Error trapping and handling: the protected block of statements; the error handler block; the Extype and Extext$ functions.
• Hints for writing correct programs: spend time testing, outline the program with pseudocode, keep programs simple, test and debug carefully, use good programming style.

The first stage of the final project is assigned this week, so it is due in your section next week along with the homework assigned. As discussed in class, the purpose of the final project is to permit some original programming on a project of interest to you. Stage one due next week may be the initial version of the program turned in as the Final Project, or may be different if you want to do two different projects. You should be sure both stages are running programs that demonstrate as wide a range of your computer skills as you can muster. Concentrate on making the programs user friendly. Use graphics, color, and sound. If you can't think of anything else more interesting, do a flashcard program for one or more of the chapters in the textbook. If you think your project might be interesting to the class, put a copy on a disk and give it to me before class next time and I'll try to run it while you make explanations.

It was decided that one quiz can be dropped and two quizzes can be made up if you have a reasonable excuse. See your TA to arrange for a makeup quiz.

Quiz 5a Solution

Lecture10. AMES 5, Thurs. 4 Feb. 1999

In solving Practice Program 6.2 it is necessary to break the program down into smaller pieces to trap the various possible date entry problems. Dates entered with more than thirty days in September, April, June and November should be detected, and the user asked to enter a correct date. Dates entered with more than 29 days in February should also not be accepted. Months larger than 12 (eg.: 13.25.98) are obviously in error, and should be trapped. More than 31 days in Jan., Mar., July, Aug. and Oct. is incorrect. Since it was requested that the date should not have leading zeros in the month and day (eg.: 01-06-98), this should also be detected in your program.

A variety of programs were presented illustrating graphical methods that might be useful in your Final Project. The first stage of your project is due next week.

Quiz 5b Solution

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