Delphi For Fun Newsletter #27[Home]
Wednesday June 19, 2002
Seven weeks have
flown by since the last newsletter. We have
managed to crank out several interesting programs
and grandkid visits are start tomorrow, so I guess
it's time to send a newsletter update. A black bear wandered
across our yard earlier
this week - it was the day after returning from a week's
absence so the place was starting to look
abandoned. Only the second time in
10 years that we have seen bears around the house.
Anyway, we'll have to schedule a few bear etiquette
sessions with the kids when they arrive, and make
sure they take the dog along for company when they
go exploring. So there are a few
negative features of life on a mountain, just not
many.
Search engines are
indexing many DFF site items these days - we
get 500 hits per day with 100-200 coming as search
engine referrals. Home page visits have
passed 20,000! This
week we added Bonny Kate Elementary School in
Knoxville to our Accelerated Reader Book Search
pages. Bonny Kate - what a cool name!
All in all, life is
good and we're still having fun!
Here are the
"What's New" items
since last time:
May 3,2002: Macro Cantu, Delphi guru and author of several excellent books, has just made an introductory text, Essential Delphi, available as a free PDF file download from http://www.marcocantu.com/edelphi/. There is also a downloadable file of associated Delphi source code. I haven't been through the entire book yet, but if you're a beginner, and maybe even if you are not, it's definitely worth a look.
May 6, 2002: Here is the first version of Four In A Row - an extended version of Tic-Tac-Toe that is played on a 7 by 6 board, requires 4 markers in a row to win, and has the added restriction that columns must be filled from the bottom up. This is the human vs. human version. If things work out, we'll build on this framework to add computer play in a week or two.
May 9, 2002: This year's World Championship ACM Programming Competition was won by a team from China. Three man teams had five hours to work on eight problems sharing one computer. I glanced at the problems and decided I might get the easiest one (problem #1 I think). The competitors were the best 64 out of 3000 teams from 1300 universities, so they are some pretty sharp cats. I'll be interested in seeing detailed results when they are available. Here's a link to more info.
Also, I ran across a well written article at delphi.about.com discussing considerations and techniques when resizing forms for various monitor resolutions. When possible, I've tried to avoid the problem here by restricting form sizes to 640 by 480 pixels. It would be nice to seamlessly scale the forms up to larger screen sizes and there are components that apparently do the job. They just aren't a standard part of Delphi (yet). May 14, 2002: Thanks to Francis M. for catching a couple of bugs in the source code for posted programs. Towers of Hanoi 2 and Towers of Hanoi 3 both used the integer edit component, TIntEdit, but it wasn't included. I've since decided that, in general, it's not a good idea to require specialized components in other distributed programs and I have generally stopped using them. I just changed TIntEdit components back to TEdits in the two tower programs and reposted them. While at it, I changed the ring animation in Tower 3 so that rings now move up off of a peg, across to the receiving peg and then down. Previous animation had used magic rings that could pass right through the pegs as they moved in a straight line from one position to the next. Also the beginner's Cannon simulation program had a reference to Unit1 in its Uses clause, even though Unit1 was not referenced or required. I had renamed Unit1, but somehow the Uses clause hadn't been updated. So that program has been corrected and reposted also. Thanks again Francis. for taking the time to email me. To all viewers - you can help make this site better if you emulate Francis and let me know when you find something that doesn't work. I'll appreciate it.
May 26, 2002: It has been a long "one or two weeks", but here at last is Version 2 of Four In A Row that was promised back on May 4th. This version adds a number of features including:
The program looks for good moves using the "Knuth/Moore NegMax variation of the alpha-beta minimax game tree search algorithm ". Whew! I pretty much understand it now, but I 'd be embarrassed to tell you how many hours were spent debugging those crucial 75 or so lines of code. The result is a fairly playable game that still leaves plenty of room for enhancement. Would-be Computer Science students, have at it. I'm going to work on beating the program when its IQ is set to 120.
May 31, 2002: A viewer from the Netherlands, informed me today about a possible enhancement to the Expressions100 program originally posted in November ,2000. The problem was to: Insert + and - signs as necessary into the string 123456789 to form an expression that evaluates to 100. Mark pointed out that allowing a leading minus sign generates one extra solution. Sure enough, with this change, there are 12 ways instead of 11. This is equivalent to specifying the digit string 0123456789 in the problem definition, so it's not exactly the same problem. But still interesting enough that I've replaced the original version with Expressions100B that has this "feature". June 3, 2002: Here's an Equation Search program that can be quite challenging to play. Given four sets of four numbers each, find an arrangement of the numbers combined with two operators to form an equation of the form (N1 op1 N2) op2 N3 = N4 that is satisfied by each of the sets of numbers. Operator choices may be restricted to from1-4 operator types chosen from +, -, ×, and ÷. Problems are randomly generated by the program. Use all four operations and allow number values up to 99 and it can take a while to "unlock the code".
____________________ Gary Darbyhttp://delphiforfun.org
"I care not what others think of what I do, but
I care very much about what I think of what I do!
That's
character!" -- Theodore Roosevelt
"The truth of the matter is that you always know
the right thing to do. The hard part is doing it."
-- General H. Norman Schwarzkopf
"You can't build a reputation on what you're
going to do." -- Henry Ford
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