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WHAT'S NEWJune 16, 2009: We are off for a week or so to help, or at least congratulate, a third grandchild in his transition from high school to college. I decided to get one more program posted before the hiatus. SortHTMLByDate is a utility which will sort a webpage with dated entries, such as this home page, into ascending date sequence. Seems like a good idea for arranging entries for archival reading once they are moved to the What's New Archives as ndexed at the bottom of this page. (Only are few have been converted so far as test cases.) June 14, 2009; Here is a "Ones" puzzle solver that finds solutions for two odometer puzzles from recent Car Talk radio programs:
My version also answers "How many numbers contain exactly 1 occurrence of 1?" and other variations for other odometer lengths up to 8 digits.
June 8, 2009:
Here is a solitaire version of the
classical Battleships game where, in addition to the ship quantities and types,
you are supplied with the number of ship parts hidden in each row or column and
a few preplaced ship parts.
Battleship Puzzle allows user play for a couple of sample problems which
will save a bushel of eraser crumbs over pencil and paper solutions
J.
May 27, 2009: Summer is rapidly approaching and programming time is
getting reduced by gardening, lawn mowing, grandchildren graduating (2 more from
high school this year). I decided to post a puzzle from my future
projects file that I had written a year or so ago but never got around to
document. The problem is to
find all 5 digit numbers that contain the same 5 digits
when they are multiplied by 3.
Then, coincidentally, yesterday's Mensa Puzzle-A-Day calendar had
another puzzle related to the number 3:
Find all 3 digit numbers, N, which together with
2*N and 3*N contain the digits 1 through 9 exactly once.
Today's Treble Puzzles posting solves
both of these.
May 19, 2009: Today's puzzle assignment, should you
choose to accept it, is to rearrange the numbers 1 through 16 in a 4x4
grid so that the sum of any two adjacent numbers, horizontally or vertically,
form a prime number. (Prime numbers are positive integers divisible
only by 1 and themselves.) No credit given for the sample shown
here. J After you give up, program
Prime Pair Sums will show you the other
2991 ways to do it. May 14, 2009: Oops - I changed everything in the DFF Library update except the actual file name in the download code. I was clued by the fact that the old version, DFFLibV12, was the downloaded 23 times yesterday. If you were one, please try it again. May 12, 2009: A housekeeping update today replaces DFF Library zipped file DFFLibV12 with DFFLibV13. The library file contains a number of units which are used in multiple programs here on DFF. Any of modified units methods included here reflect minor bug fixes or have already been included in source code of programs which required the enhancements . Library units which are currently duplicated in program source code will be removed as those programs are updated, so no need for any immediate action by programmers. The library zipped file file contains text file DFFVLib13.txt describing the changes in this version. One program, Big IntegersTest, has also been reposted with new buttons to test the five new methods in our large integer class, TInteger, which resides in unit UBigIntsV3.
May 7, 2009: The objective of the
Forbidden Connections Puzzle is
to enter the digits 1 through 6 in the circles in this diagram in such a way
that no number is connected to its adjacent value. (For example, there can
be no line connecting the "3" circle with the "2" circle or the "4" circle,
etc.) The program allows user play, finds the two valid solutions, and gives
user hints if
needed. May 2, 2009: I decided last night that Parabolic Reflections posted yesterday should be able to display more information about the intermediate steps in defining the reflected ray. Parabolic Reflections Version 3.1 posted today corrects that deficiency.
May 1, 2009: A week of algebra, geometry,
and trigonometry refreshers was enough to convince me what I was already quite
sure of, but had never proven, that parallel rays striking a parabolic surface
are indeed all reflected to a common focal point. Here is a
Parabolic Reflections
program which applies the math to see where it takes us.
The web page steps through the required math. April 22, 2009: It has been a while since we have had a beginners program posted, so here is one that some might have fun with. Number Words converts any input integer between 0 and a million to words. So 456,789 as input for example, displays the result "Four hundred fifty-six thousand seven hundred eighty-nine". About 60 lines of user written code do the job.
April 12, 2009: Concentration is the card
game requiring that pairs of face-down cards be drawn and replaced until a match
is made. In case that game is too easy,
Concentration Version 2 adds the option
of requiring sets of three matching cards be found before they are removed. April 6, 2009: Brute Force is one of my favorite programs on the site. It can solve a wide range of puzzles/problems which have a restricted range of integer solutions. Give the program the possible variable values and the equations describing the conditions to be met, and the program does an exhaustive search for sets of values satisfying the conditions. The download files include 24 sample problems. Brute Force Version 2.3 posted today allows problems with fewer variable values than variables to be solved. The newly included "Binary Conversion" sample problem finds numbers between 6 and 16 with the two middle digits in the binary representation having the same value. April 4, 2009: While the design of the bookmark might be perfect, there was room to improve the implementation. Perfect Bookmark V4 was posted today with a few image and font handling enhancements.
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