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Eberhard's PL/I Problem

In the last issue of "The PL/I Connection" I presented a PL/I problem and promised to give a solution in the next issue. That was in December 1997. I'm glad to have the opportunity to keep this promise in "The PL/I Newsletter" now.

If you remember the problem: Write a subroutine which computes the ratings of the game Master Mind. An additional requirement was, do it in eight statements or less.

For those of you who missed the original article and first want to find a solution themselves, here is the URL:
http://www.ibm.com/software/ad/pli/pli1297.htm
I reviewed the postings of 1998 in the newsgroup "comp.lang.pl1" and here is my favourite solution posted by Clement McGann (please, excuse my editorial changes):

The number of white pins is the sum of all places where the hidden pins and the guessed pins are equal. (Comparison of two arrays yield a bit array which is converted to binary for the purpose of computing the sum. I may be biased but I like this statement!)

Then for each color it is checked how many times the color occurs in the hidden and in the guessed code. (Again comparing a scalar to an array yields a bit array. You can read "sum(I = Hidden)" as: Sum up all places where I is equal to a value of the array Hidden.) In Master Mind only relevant is the minimum of the two values. If you add these numbers you get the number of both black and white pins. So you have to subtract the number of white pins in order to know the number of black pins.

This Month's Problem
The problem of today uses some new features of the Visual Age PL/I compiler. Given an ordinal variable T which can assume two values T1 and T2, I want a function also named T which returns the ordinal value when the binary value is passed to it:

If you have a running solution you can check if you have presumed big endian or little endian representation, respectively :-)

I hope this problem is a challenge to you. Have fun, and, perhaps, learn something new. Afterwards you can decide yourself if your product is programmed in "good" or "bad" style.

You may post solutions to comp.lang.pl1, or if you prefer a more private venue, mail your solution direct to Eberhard at sturm@uni-muenster.de

From the Web ...

New Update for VisualAge PL/I.

• Workframe has been altered to work under FFS.
• The debugger has been changed to work under Windows 2000.
• Initial support for UTF-16 Unicode is provided via the new WIDECHAR attribute, to enable Unicode files to be read and written. New built-in functions allow handling of WIDECHAR strings, and include
  ONWCHAR, ONWSOURCE, WCHAR, WCHARVAL, WHIGH, WIDECHAR, WLOW. Other built-in functions include:
  ACOSF, ASINF, ATANF, COSF, EXPF, LOG10F, LOGF, SINF, TANF, and
  CHARVAL, ISIGNED, IUNSIGNED.
• The Programing Guide, Language Reference Manual and Messages and Codes Book have all been updated.
• PL/I can be called from VisualBasic and COBOL.
• Enhancements to the preprocessor include support for:
  • Arrays in preprocessor procedures
  • WHILE, UNTIL and LOOP keywords in %DO statements
  • %ITERATE statement, %LEAVE statement. %REPLACE statement
  • %SELECT statement
  • Additional built-in functions are COLLATE, COMMENT, COMPILEDATE, COMPILETIME, COPY, COUNTER, DIMENSION, HBOUND,INDEX, LBOUND, LENGTH, MACCOL, MACLMAR, MACRMAR, MAX, MIN, PARMSET, QUOTE, REPEAT, SUBSTR, SYSPARM, SYSTEM, SYSVERSION, TRANSLATE, ans VERIFY.
• Various changes have been made to provide consistency across mainframe and PC platforms.
• Some bugs have been corrected.
• You can download the fixpack for Windows NT and Windows 2000, but note that it is 150 Mb.

Buy PL/I on the web

Usefulle Webbe Lynx ...

The PL/I Connection newsletter.

The PL/I Connection Newsletter No. 11 , December 1997.

The PL/I Connection Newsletter No. 10 , April 1997.