April 5, 2014
Delphi For Fun Newsletter #72
One of my earliest memories is of the roadside Burmashave signs while riding with my folks in our '47 Buick to visit Aunt Pearl. The signs came in sets of 5, spaced about 100 yards apart. The set that comes to mind every April is "Spring has sprung", "The grass has riz", Where last year's ", "Careless driver is", "Burmashave". Signs 1 and 2 have happened, so drive carefully! We have been feeding about 100 lbs of corn per month (to the deer and wild turkeys), and 10 lbs of bird seed (to the little birds during the day with the bandit raccoons and a skunk cleaning up on the night shift). They enjoy the food and we enjoy watching them. (Well, the skunk not so much!). We're all happy to see the end of the "starving season".
produced a typical mix of puzzle solvers, utility programs, and updates to a
couple of my favorite "oldies but goodies". Namely:
Here are links to all the 1st quarter postings.
January 6, 2014: We visited our son and family in Alabama for Christmas and spent some time playing games including Scrabble. I'm a fairly smart guy, but most males, including me, are genetically handicapped when it comes to language skills and the girls (wife and granddaughter) beat my son and me soundly. Sarah's Scrabble set includes a large book with all valid words and a 3 minute timer. We used most of our 3 minute turns frantically trying to verify that potential words were actually in the book. That led to today's Scrabble Search helper program. Given a set of available letters and information about where they might connect to words on the board, the program will list legal words to choose from. As the author, I claim the right to use it during games with family and to extend usage to other males in the game. Now if the girls will only agree J.
January 12, 2014:
back to the Mensa Page-A-Day calendar this year and the problems are much
more program-worthy than last year's puzzle calendar. Here's a
Matchstick Puzzle from the
January 2 page requiring you to "burn" segments of matches on a grid in
such a way that the number of burned segments in each column and row matches
given target values. The program makes it easier than pencil and paper
to burn and "unburn" match segments to solve the puzzle.
January 27, 2014: A change at our host site prevented DFF site updates and it took me several days to recover site formatting. If you run across format errors or missing or erroneous links, please drop me a line using the feedback link.
February 1, 2014: Adapting programs to display properly across multiple screen resolutions is a persistent problem for programs which run on unidentified remote systems. I've made a start today by modifying several programs to display properly on screens from 1920x1200 (my system) down to 1024x720 (likely the lowest for LED screens). Links to changed programs are included at Screen Resolution Considerations in our Delphi Techniques section. Please let me know if you find truncated/overlapping display elements in these (or other) programs.
February 5, 2014: Version 1 of the Text Search program scanned a file and reported matches to a given string. TextSearch Version 2.0 posted today adds these user requested features:
February 6, 2014: An error in the FastMult (Fast Multiply) procedure in our Big Integers unit was corrected today. The error was introduced in the November, 2013 update and returns invalid results multiplying integers of more that 1000 or so digits. The corrected UBigIntsV4 unit is available in today's posting in DFF library zip file DFFLibV14_6Feb2014. This introduces a new naming protocol for the library files to include the date and enable better tracking of minor updates.
The BigIntsTest program was also reposted to include the changed unit. As a matter of interest, FastMult is 4 to 5 times faster than the regular Mult procedure when multiplying two random 50,000 digit integers (0.46 vs. 2.1 seconds, and the results now agree)!
February 9, 2014:
Brute Force is one of my favorite programs because it solves so many puzzles that can be expressed as algebra problems, including this one. We need to assign coins to the empty squares so that the sums match the given numbers. That requires 12 equations (5 rows, 5 columns, 2 diagonals) with 17 variables (the empty squares) with 4 possible values for each (empty, nickel, dime, quarter). The Brute Force button found the solution in about 30 minutes and verified that it was unique in 15 minutes more after searching all 17 trillion possible solutions.
Brute Force Version 3.0 fixes a problem with Incremental Solving when multiple variables can have the same value as in this puzzle . Incremental Solve works by enumerating each valid solution for the 1st equation, then testing the 2nd equation to see if there could be a valid solution given the trial solution for the 1st, then the 3rd given 1st and 2nd, etc. Once I fixed the problems that kept it from working on this case, the Incremental Search button finds the unique solution in 0.05 seconds and takes an additional 0.10 second to verify that the solution is unique!.
This problem is now included (as "Mensa Puzzle 2-5-14 Calendar.prb") along
with the other samples in program downloads.
February 20, 2014: The Text Search program version posted a couple of weeks ago writes lines or portions of matching lines to a file. The fellow who requested likes the way it works, but we disagreed on what the default options should be. Text Search Version 2.1 resolves our differences by remembering options selected from run to run. Everyone is now happy.
February 28, 2014: A viewer working on a playback program for Chess games was having trouble building the keys for each rank using FEN notation. FEN uses letters for the chess pieces (P for Pawn, B for Bishops, etc.) and numbers to represent the count of consecutive empty cells. He didn't tell me that objective though until I had written this little demo program, Count Grid Cells which builds keys based on randomly placed letters on an 8x8 grid. The link is to a page of beginner's level Delphi programs. Click on the link within that page or scroll to page bottom to find the download links.
As a bonus, I finally took time to develop a simple way to remove that irritating highlight color drawn for every selected cell in a TStringGrid. I installed it for the two grids it in this program and like so much that I plan to add it to our DFFUtils utility library unit.
March 6, 2014:
Our Oil Tank
Capacity Chart program displays a chart of remaining gallons for various
liquid depths for a number of standard fuel oil tanks. I recently added
Version 2.1 to include a couple of new sizes at a user's request. Version
2.2. posted today, ,allows users to edit, add, or delete dimensions of defined
tanks and to
print generated charts. Fractional inch dimensions now allow my
tank chart to match the nominal capacity within a gallon for all depths!
Here is yesterday's Mensa Calendar puzzle which prompted today's program. My
language-oriented, crossword-addicted, wife solved it in less than 10 minutes. I
got two of the three words in the line 2 puzzle in 10 minutes; then decided it
was programming time!
Just in case you don't already have the dictionary, both the program and the dictionary are included in the
executable zip file download.
March 24, 2014:
March 29, 2014:
A viewer was having trouble getting the program to work on his system,
receiving "invalid data format" errors. I could duplicate the error when
"Dual Channel" input was specified when only monaural input was available.
The problem persisted because the single/dual channel option was saved and
restored across multiple runs. Oscilloscope
4.2.3 posted today is a temporary fix which resets the input format to
monaural when the program is started. I'll work on a better fix next
Dr; Seuss quotes to inspire you!
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