Lectures week 5, AMES 5, Fall 1998

Lecture 14. AMES 5, Monday 26 Oct. 1998

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.

All of these concepts are illustrated by the Example Programs which you will modify in your homework.

Original Practice Programs are 6.1 and 6.2.

Lecture 15. AMES 5, Wed. 28 Oct. 1998

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.

Lecture 16. AMES 5, Friday, 30 Oct. 1998

Exam 1: Closed book, closed notes, covering Chapters 1-5 of the textbook.

See the solution of the Sample Exam.

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