# What's New - March 2001

### [Home]

 J March 15, 2001:  It may be too late to make use of this Windchill program for  this year (I hope).  And the "International Windchill Conference" recently agreed to change the formula to make it more accurate for next year.   But I wrote the program one cold, windy day a week or so ago and it's finished so I may as well publish it.   The program is in the "Intermediate level" because it addresses a couple of subtle coding problems with the Delphi's trackbar component (TTrackbar).  Not the kind of problems a beginner needs to worry about.  Forgot to mention, I also posted a short article on Proof by Contradiction in the Math Topics section a few days ago.  The idea is to assume that what you are trying to prove is not true and then see if this leads to some  impossible conclusion.  The example given  shows how   Euclid used this technique to prove that there is no largest prime number.      March 14, 2001:  Have you ever wondered how those "sort column" features work for a displayed grid?  Probably not.  But here's another Delphi Techniques  program  that shows how to do it anyway.   Grid Sort displays a stringgrid of random data. Click on the header of any column to re-sort the rows in increasing sequence by that column.   March 13, 2001: Here's a program which illustrates accessing drive and file information.  If you need to locate the CD-ROM or Network connected drives in code or want to access all files matching a certain mask, you'll get some ideas of how to do it from this DriveDemo program in the Delphi Techniques section.    March 11, 2001:  The Big Factorials program is available.  It calculates N! (1x2x3x4....xN) for values of N up to 999.  999! contains over 2500 digits,  a very large number indeed.  The distance from the Sun to our furthest planet, Pluto, is approximately 13! kilometers  and it's only 23! kilometers across the known universe.   Since these numbers are far larger than any computer can handle directly, we just wrote a program that works like a very fast human with a pencil and paper.   We also added an article in Delphi Techniques section describing how to let the user stop execution of a long loop.  March 6, 2001: The Programs subweb keeps growing.  As a result, things keep getting harder to find, even for me - and I put them there.  I added a search button to the bottom of the left side index panel today just to see how it works.  I already see that it doesn't search subwebs (like Delphi Topics and Math Topics, but it's a start.          March 5, 2001:  MAZE, a maze generator program is available!  The program chooses the path through a maze.  You control the size, shape, colors, and complexity of the maze.  Generated mazes can be solved on  screen, saved to disk, or printed.  This one of the more complex programs posted so far, mainly because there are lots of functions.  But examined one at a time, you can probably worked your way through them and learn some coding techniques.   I believe this is the first program here that uses Delphi's printer and filestream controls.         March 1, 2001:  Raising a number to an integer power?  IntPower Demo is not really a puzzle,  it just compares the timing of four ways to do it: brute force, recursion, powers of 2, and Delphi's built-in IntPower function.  I've added  download links at the bottom of the  Timing and Recursion  pages if you're interested.