Lecture 9. MAE 5, Tues. April 30, 2002

From the course outline we see the reading assignment this week is Chapter 6 on Finding and Correcting Errors. Laboratory Quiz 2 will be given in Sections, and will involve solving programming problems similar to those you have been doing as Practice Programs for homework. The lab quiz is open book and open notes, but you can't discuss what you are doing with your fellow students...only your TA. Project 1 is assigned this week, so it is due by Friday afternoon of next week (May 10, the same due date for all Sections). The minimum number of commands for the first project is 15. You are free to use more than 15 commands if they will improve your project. Give it a title. See guidelines.

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). The TRACE command doesn't work for TB Bronze, only 2.72.

Some of the methods presented include:

• Playing computer...reading through a computer program as though you were the machine. This is what you are supposed to be doing when you take a quiz.
• Temporary PRINT statements.
• The DO TRACE command (TB 2.72).
• The BREAKPOINT command.
• Calculation errors.
• Error trapping and handling: the protected block of statements; the error handler block; the Extype and Extext$ functions. See PP6.3.
• Hints for writing correct programs: spend time testing, outline the program with pseudocode, keep programs simple, test and debug carefully, use good programming style.

Quiz 5a Solution

Self Test Question Answers Chapter 6. Study these in preparation for Quiz8, Spring 2002 (next week....see version given previously)

Advanced techniques: Have a look at the use of arrays and modules in these programs. Copy and try deal, which deals a bridge hand, using module cards. You can cut and paste to produce card game projects (sort the hand, count honor points, etc.).

The program for dice throwing shown in class last week (adapted from one in TBRef by Prof. Herz) demonstrates the functions RND and INT, and the commands RANDOMIZE, SOUND and PAUSE.

Lecture 10. MAE 5, Tues. May 2, 2002

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 projects.

Quiz 5b Solution

Self Test Question Answers Chapter 6. Study these in preparation for Quiz 9, Winter 2002 (next week....see version given previously)

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