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July 3, 2015

Delphi For Fun Newsletter #77

In the non-computer arena, we've enjoyed seeing last year's baby twin deer reappear - the girl with her new spotted baby and the boy sporting a new pair of 5 inch velvet antlers.  Best of all, Mama (now a Grandma) is back with the next pair of twins bouncing around the yard.  Lots of rain promises a bumper crop of wild blackberries and tame blueberries this year.  We're hoping that there are enough blackberries for the deer and bear to share with us.   One brave crow had to sacrifice her life to a shotgun in order to save the blueberries for us humans.  Yum-yum (for the berries, not the crow!)       

Only eight program postings this quarter, but they cover the range from simple to advanced complexity, user to programmer oriented,  and "just for fun" puzzles to serious mathematical topics.  

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April 13, 2015:
 Here's an interesting little puzzle that requires some human thought to solve efficiently: 
A farmer tells his son to select five watermelons to take to market. Because the watermelons are sold by weight, they must be put on a scale before the trip to town, but the son makes a small mistake and weighs them in pairs. Here are the weights he comes up with, in pounds: 20, 22, ,23, 24, 25, 26, 27, 28, 30, 31.  How much does each of the watermelons weigh?  (Source: Sit & Solve® Brainteasers (Sit & Solve® Series) 
The Weighing Watermelons program posted today implements the solving strategy.

April 19, 2015:
A buddy of mine is designing a Veteran's Day monument which will consist of panels representing the Armed Forces services and aligned in such a way that the sun will cast a shadow on the memorial plaque on November 11 at 11:AM.  At his location, he thought that the sun would cast the shadow again in February when the the sun will be at the same altitude at that hour.  I took advantage of the opportunity to educate him about the  "analemma" figure 8 shape of the sun's path through the sky and assure him that the February sun at 11 AM will be about 10 degrees further East than the November path.  I updated  AstroDemo Version 2.0, our Astronomy unit test program, with an "animated" analemma. That option  helped me determine that at 11:11 AM in Lucedale, MS, the crossing point of the figure 8 occurs on February 12 as days are getting longer and August 29 on the way back down, so no problem for Jim's project!  
 
 

April 29, 2015: 

No L	Yes J!

Three points are placed randomly on the circumference of a circle. What is the probability that all three points lie within the same semicircle?   Check out Circular Reasoning to verify your answer.
 

May 11, 2015: 
A viewer discovered a memory leak in our Big Integers unit which carried over to the Big Float unit.  UBigIntsV4 allows mathematical operations on integers whose size is only limited by available memory and UBigFloatV4 extends the extended precision feature to floating point numbers using UBigIntsForFloatV4 for the integer parts.   The Free method in both of the big integers unit released the memory specifically allocated by the program but neglected to call the inherited Free method which releases the memory taken by the system when the integer object was created.    Today's' postings include a revised library zip file, DFFLibV4_11May2015 containing the revised units.  Two test programs, BigIntsTest and BigFloatTest were modified to report allocated memory after each operation to verify the correction and to help indentify future memory release problems.

May 31, 2015:  

Just time to squeeze in one more little program this month.  Outdoor activities have taken up most of my time recently and most of the daily Mensa Calendar puzzles are either solvable by programs I've already written or are not amenable to being solved by computer.  But yesterday's offering  was a good candidate so here it is:  "A surprising number of U.S. state names contain multiple pairs of letters which form standard two-letter state abbreviations. For example ALABAMA contains two: AL and MA (Alabama and Massachusetts).  If we don't allow overlapping abbreviations, there is only one state name that contains as many as  four abbreviations.  Can you find it?"    Search State Abbreviations is a 50 line program which finds the answer by listing and counting the embedded abbreviations for all 50 states.  The preceding link is to a page of twenty or so Beginner's level programs.  Just click the bookmark or scroll to the bottom of that page to download the source or executable for the new  program. 

 June 10, 2015:

Black clouds - not so good

Better now

A program illustrating many graphic manipulation effects in Delphi was posted 12 years ago.  It was largely written by a young Czech programmer, Ivan Sivak, who I'm sure has moved on to bigger and better things by now.  I made only minor changes to his code before posting it.  A fix was posted today in the Contrast/Brightness section of Graphic Effects correcting a problem of white or light gray pixels displaying as black..
  

June 17, 2015:  
A License Key Generator program was posted several months ago to explore how unique  keys might be generated to allow a program to verify owner or expiration date information.   To my surprise, the program was recently flagged as a "Keygen Trojan" by a well respected security scanner.  I revisited the source code and made a few formatting and spelling enhancements and the warning disappeared.  So, just in case, I reposted the License Key Generator V1.1 program today.    

June 29, 2015:
  Acrostic Variation, posted today, implements a solver for this Mensa^® calendar puzzle from March 16, 2015.  It uses a search technique probably used by most human solvers; concentrating on the word intersections to find candidates; the program just does it a lot fasterJ.  
 

Persistence

	"If people knew how hard I had to work to gain my mastery, it would not seem so wonderful at all." - Michaelangelo (Artist/Sculptor)
	"Talent is cheaper than table salt. What separates the talented individual from the successful one is a lot of hard work." - Stephen King (Author)
	"History has demonstrated that the most notable winners usually encountered heartbreaking obstacles before they triumphed. They won because they refused to become discouraged by their defeats." - B. C. Forbes (Journalist)
	"An inventor fails 999 times and, and if he succeeds once, he’s victorious. He treats his failures as practice shots." -Charles F. Kettering (Inventor)
	"Hasten slowly, and without losing heart put your work twenty times upon the anvil." -Boileau (Poet)
	"Tyranny like hell, is not easily conquered yet we have this consolation with us, the harder the conflict, the more glorious the triumph. What we obtain too cheap, we esteem too lightly; it is only dearness that gives everything its value.”   Thomas Paine (Patriot)

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