March 15, 2001: It may be too late to make
use of this Windchill program
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
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
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
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.