Structured Programming in Basic Problems
© 1998 by Dr. Thomas W. MacFarland -- All Rights Reserved
Instructions: Review the following program and see if you can predict the outcome by completing a "pencil trace" of the code. Program output is provided at the end of this page. Compiler: The program was prepared using GWBasic, which requires the use of line numbers.
10 REM This program demonstrates the use of LEN, 20 REM WHILE WEND, and Boolean logic with OR. 30 PUPPY$ = "" 'Set variable to null. 40 WHILE LEN(PUPPY$) < 5 OR LEN(PUPPY$) > 10 50 PRINT "Enter the name of your puppy at the ? prompt." 60 INPUT PUPPY$ 70 PRINT PUPPY$ 80 WEND 100 REM Enter Spot on the 1st iteration. 110 REM Enter King Rex the Wonder Dog on the 2nd iteration. 120 REM Enter Cherry on the 3rd iteration. 999 END 10000 REM And the answer is ... 10010 REM Enter the name of your puppy at the ? prompt. 10020 REM ? Spot 10030 REM Spot 10040 REM Enter the name of your puppy at the ? prompt. 10050 REM ? King Rex the Wonder Dog 10060 REM King Rex the Wonder Dog 10070 REM Enter the name of your puppy at the ? prompt. 10080 REM ? Cherry 10090 REM Cherry