What's New - February 2001


February 26, 2001:  Perfect, Amicable, and Sociable numbers are the subject of today's program , AliquotSums.  And you'll learn a new word as a bonus.  

February 21, 2001:  Another addition to the Delphi Techniques section.  I posted today an integer list counterpart to Delphi's TStringList, a useful string list component.    I could have used TIntList in many previous programs but really needed it for the current project, (perfect, amicable and social numbers).    

Go here to check out the new TIntList class.   

February 18, 2001:  I finally got tired of manually adding code to validate numeric input from the user.  Today I added visual components TIntEdit and TFloatEdit  to replace TEdit when numeric entry is required.   These are not very sophisticated but they are small and seem to do the job.   You can check them out and download from this Delphi Techniques page .    This might be the time to experiment if you haven't yet played with writing your own components.   

February 17, 2001:  A Delphi version of Mastermind, the famous  game with the objective of finding a secret pattern  of colored pegs is ready to enjoy.   And if you think discovering the pattern is challenging, wait 'till you try to understand how the program solves it.  The algorithms, largely from the algorithm lover's best friend - Professor Donald Knuth, are great fun to study.    Have at it!   

February 11, 2001:  Today's contribution is a version of the Eight Queens problem that I call Eight Queens Plus.   The traditional Eight Queens problem asks you to place 8 queens on a standard chessboard in such a way that no queen can attack another.  This is equivalent to requiring that no queens be in line vertically, horizontally or diagonally.  This version requires, in addition, that no queen occupy either of the two main diagonals.  There are 3 versions of the program, Version 3 finds multiple solutions, has a graphic display of the board and allows user play.   It has about 500 lines of code and so qualifies as advanced under our size criteria, even though the code is not particularly complex.  The first 2 versions are considerably smaller.     

February 5, 2001:  Akerue is ready!  This is a word-finder game where you try to find as many words as possible in a random  array of letters.  The name is based on a Turbo Pascal version published by Borland as part of a package called Word Wizard about 15 years ago.   In this version you match wits with the computer by finding all the words you can, then give the computer a chance.  If he can't find enough words that you missed to get a higher score, you win!   Akerue's  score usually exceeds mine by a factor of 10.    

Some new (for this site) Delphi features are introduced including 2 dimensional dynamic array handling, use of Application.OnIdle event exit to perform background processing,  and the use of TMediaPlayer to provide some audible feedback to the user as he finds words. 

I also discovered this week that a unit used by Crossword Helper doesn't seem to be included in Delphi Standard.  I've updated  the source zip file to include masks.dcu.  If you have Pro or Enterprise versions, you don't need it.  If you have Delphi Standard,  save up the extra $ to upgrade - it's worth it just for what you'll learn browsing the included source code.