Landon Curt Noll
4f95e3f3d6
We fix more markdown links in markdown files that refer to files internally to the web site. Added tmp tools to find and print various markdown links: * `tmp/md-links.sh` - print all markdown links * `tmp/md-token-links.sh` - print all markdown links that start with a **%%TOKEN%%** * `tmp/md-local-links.sh` - print all markdown links to a local file * `tmp/md-link-paths.sh` - print local file paths referenced in markdown links Fixed a number of markdown formatting problems with `thanks-for-help.md`. Fixed markdown links to files in `thanks-for-help.md`. Improved heading levels in `thanks-for-help.md`, and made entry sections consistent. Changed all markdown links that end in "))" to end in a better way. Explained in `markdown.md` why we are avoiding markdown links that end in "))". Ran `make www` to perform the above. TODO: Fix stuff we broke by mistake doing the above. TODO: Fix more broken markdown links.
3.4 KiB
To build:
make all
```
There is another version which is the original entry. See [alternate
version](#alternate-code) for details as to how to use and why it was made the
alt version.
## To use:
``` <!---sh-->
./clock1.sh
./clock2.sh
./clock3.sh
Try:
./try.sh
Alternate code:
The original version had a display problem in modern systems which somewhat affected the usability of the program. This alternate code, the original, is provided, to show the differences.
Alternate build:
make alt
Alternate try:
./try.alt.sh
Judges' remarks:
Time and time again, Brian Westley seems to come up with a winning entry! We are amazed at how much is being done with only one relatively short line. We think you will as well if you take the time to understand it.
Author's remarks:
This 1-line program allows various analog ASCII clocks to print out the time; the ASCII clock is built from the command line arguments, so many different types of clocks can be generated. Three different scripts are supplied to print out a grandfather clock, a mantle clock that runs backwards, and a linear-style clock. (they are clock1.sh, clock2.sh, and clock3.sh.
The program makes the following (possibly non-portable) assumptions:
-
Command line strings can be written to.
-
argv[0]can be written to as if it were along *. -
The first three elements of the
struct *returned bylocaltime(3)are seconds, minutes, hours, and all areints. -
My sample scripts assume ASCII, though this is not inherent in the code, just my sample scripts.
These assumptions are pretty reasonable. 2) can be eliminated but makes the code larger.
The code is simple; the arguments passed are:
./westley minute_map hour_map hand_symbol clock_image
The program merely takes the minute (0-59) and the hour (0-23)
values, looks up the offsets in minute_map and hour_map
and writes the hand_symbol for each into the clock_image
string. This string is then printed.
The for() loop starts by calling time() with argv[0], so
the time value (a long) is written into the program name.
The for() control value is argc, which starts at 5, but
the /=2 statement is executed before the test, so the for()
loop is executed twice, with h=2, then h=1 (for hour & minute).
The statement of the for() loop takes the hour or minute
field of the struct returned by localtime(3) by casting it
to an int * and dereferencing element [h]. It is slightly
smaller to use the trick h[(int*)localtime(*m)] instead of
((int*)localtime(*m))[h].
This value is in turn indexed into the hour_map or minute_map
parameter to determine where the 'hand' symbol should be
written into the clock_image.
Note that the hands move in a quantum fashion; 3:59 looks deceptively like 2:59, since the hour hand will be at the 3 position. It won't move until both hands click over at 4:00.