What's New - February, 2011
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February 1, 2011: Red letter day! A reasonably priced "Starter" version of Delphi is available! Delphi XE Starter Edition is $149 (or apparently $149 Euros) if you have any prior version of Delphi (or almost any other development package). See http://www.embarcadero.com/products/delphi/starter for details.
I downloaded mine yesterday and tried converting LPDemo as a first test. There is a small problem with a different default string format which will only show up if sia ngle byte character sizes are assumed. LPDemo happened to do that but LPDemo Version 2.1 posted this evening seems to fix the problem.
I'll be working (slowly) on recompiling the several hundred DFF programs under Delphi XE and will likely create a page or section of the DFF website with conversion and compatibility notes. I especially invite feedback on your experiences with this long awaited new version.
February 7, 2011: A couple of times each year, I get an email from a student or teacher using our "Reaction Times" program to conduct some study or experiment. Sometimes they merely have questions about using the programs; sometimes the need modifications. That was the case with a team of graduate students at a Danish University Hospital who are using the program to study fatigue effects on stimulus response times for recovering stroke victims. Today's posting: ReactionTimes Version 3.2 implements a few commonsense features that should help them.
February 12, 2011: Several times a year I end up with a small program that I write just because it's the surest way to find the answer to some puzzle or problem I run across. I post some of these in our Beginner's page in the Delphi Techniques section of DFF. Here's the latest example, Pecking Order, where writing the 30 lines of code just seemed easier than doing the algebra:
Four sparrows found a dish of seed,
Fine bird food, no common seed.
Said Pip: "In turn each take 2 grains
And then a third of what remains
It's me as first, then Pep, then Pop,
With Pap the last and then we stop."
But Pap cried out: "It isn't fair.
Mine's two seeds less than half Pep's share."
Old Pip was boss, his word was law,
So little Pap got nothing more.
Poor Pap, his share was rather small!
How many seeds were there in all?
From: "Challenging Mathematical Teasers",
J.A.H. Hunter, Dover Pubs, 1980
February
22, 2011: Maze, Version 3.1,
our maze puzzle generator/solver program was posted today. No functional
changes today; it just fixes a minor bug which prevented erasing all
intermediate path segments when a user
"backtracked" to a previous point with a mouse click.
February 25, 2011: One of the oldest and still one my favorite programs on the site is Brute Force. It uses exhaustive search to solve systems of linear equations with solutions restricted to specified integer values. It's surprising how many puzzle problems meet these conditions, Brute Force Version 2.5 adds the "mod" remainder operator to help find a six digit even number that must meet some other conditions, but the "even" condition is the one that mod helps determine (the equation F mod 2 = 0 defines is the constraint that F be even).