Add 2000/rince/try.sh + format/typo check
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@@ -1,7 +1,7 @@
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## To build:
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```sh
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make
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make all
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```
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@@ -36,8 +36,7 @@ That's not a bug, that's a feature.
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### Try:
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```sh
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make dmy2jd
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./rince 0.001 `./dmy2jd 7.8 1 1610`
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./try.sh
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```
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@@ -89,6 +88,7 @@ A Julian day is defined to be the number of days since January 1st in the year
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[dmy2jd.c](dmy2jd.c). Run it with `day_float month year` as arguments. See below
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for an example.
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### What it does
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This program plots the positions of the four [Galilean
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@@ -98,8 +98,8 @@ moons](https://en.wikipedia.org/wiki/Galilean_moons) of
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location on Earth, but I assure you that the
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[parallax](https://en.wikipedia.org/wiki/Parallax#Astronomy) is minimal!
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The moons are labelled with Roman numerals from I to IV. I being the
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closest to the planet and IV being the furthest. They are:
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The moons are labelled with Roman numerals from `I` to `IV`, `I` being the
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closest to the planet and `IV` being the furthest. They are:
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```
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I Io
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@@ -130,6 +130,7 @@ confusion, please consult the following chart (\*):
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(\*) Not to scale.
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### History
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Galileo discovered the moons in January 1610.
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@@ -174,9 +175,9 @@ orbit the sun, and not leave a moon behind!
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Thus we can plot Galileo's discoveries using the following three plots:
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```sh
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./rince 0 `./dmy2jd 7.8 1 1610`
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./rince 0 `./dmy2jd 8.8 1 1610`
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./rince 0 `./dmy2jd 10.8 1 1610`
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./rince 0 $(./dmy2jd 7.8 1 1610)
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./rince 0 $(./dmy2jd 8.8 1 1610)
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./rince 0 $(./dmy2jd 10.8 1 1610)
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```
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However we can go one better by seeing what Galileo would have seen if it
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@@ -184,14 +185,14 @@ wasn't cloudy on the 9th. Try:
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```sh
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./rince 0 `./dmy2jd 9.85 1 1610`
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./rince 0 $(./dmy2jd 9.85 1 1610)
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```
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to see what he was missing out on. I wonder what he'd have made of that!
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Galileo discovered the fourth moon a few days later.
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I've tried typing these dates in to two Java based Jovian moon plotters,
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I've tried typing these dates into two Java based Jovian moon plotters,
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but both I tried had problems dealing with dates earlier than 1900. More
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professional software, such as the
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[SkyMap](http://www.bmsoftware.com/skymappro9.htm) gets these values
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@@ -204,6 +205,7 @@ Century, so clearly this program has a long history :-) A more complete
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description of the origins of Julian Days can be found at
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<https://web.archive.org/web/20001206152200/http://aa.usno.navy.mil/AA/faq/docs/millennium.html>.
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### Assumptions
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This program assumes:
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@@ -226,7 +228,9 @@ If this is not the case the program will crash.
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Pro](http://www.bmsoftware.com/skymappro9.htm) show that there is a good
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similarity (but not much more) up to about 500BC.
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6. The code definitely is not portable - it will produce incorrect results if run from the surface of Mars.
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6. The code definitely is not portable - it will produce incorrect results if
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run from the surface of [Mars](https://science.nasa.gov/mars/).
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### Obfuscations
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@@ -255,7 +259,7 @@ common tricks. Taken through the standard rounds listed in the
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4. C pre-process the source ignoring `#define` and `#include` lines
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This does a good job of expanding out the code, but it does not
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clarify things greatly. The use of `#defines` has been restricted
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clarify things greatly. The use of `#define`s has been restricted
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primarily to a space-saving mechanism.
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Additionally, the use of `typedef`s means that the types used are
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@@ -263,7 +267,7 @@ common tricks. Taken through the standard rounds listed in the
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5. Run it through a C beautifier.
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GNU indent seems to do a reasonable job, provided that the
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GNU `indent(1)` seems to do a reasonable job, provided that the
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`#define`s are expanded first. This doesn't lay the algorithm
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particularly bare though as most of the obfuscations are not
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simple code layouts.
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@@ -274,10 +278,11 @@ common tricks. Taken through the standard rounds listed in the
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by taking a large string and breaking this down into a series of
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opcodes (which I have termed J-code). These are then executed.
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To get to the real method of how it works, you need to decode
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the opcode string (which deliberately contains as many `;`, `{` and
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`}` symbols as possible), which will give you a reverse-polish
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notation chunk of mathematics.
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To get to the real method of how it works, you need to decode the opcode
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string (which deliberately contains as many `;`, `{` and `}` symbols as
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possible), which will give you a [Reverse Polish
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notation](https://en.wikipedia.org/wiki/Reverse_Polish_notation) chunk of
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mathematics.
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Sensible people amongst you will simply refer to the referenced book :-)
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@@ -294,9 +299,9 @@ common tricks. Taken through the standard rounds listed in the
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I'm sorry to say that there are several warnings issued by the
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compiler.
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Firstly, the return type for `X()` is not specified, so it defaults to int.
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Firstly, the return type for `X()` is not specified, so it defaults to `int`.
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Horror of all horrors - this function does not return an integer type (it
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doesn't contain any specific returns). The return value from `X()` is not
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doesn't contain any specific `return`s). The return value from `X()` is not
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accessed. The same problem occurs in `main()` - it does not return. However
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`main()` never exits unless there is a serious error.
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@@ -318,11 +323,11 @@ common tricks. Taken through the standard rounds listed in the
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-Dusleep={time_t v[2]={0,10000};select(0,0,0,0,v);}
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```
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gcc complains about "unreachable code at beginning of switch
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`gcc` complains about "unreachable code at beginning of switch
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statement", although removing some of this code will prevent
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the algorithm from working.
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gcc also suggests that I should be using extra parenthesis, but
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`gcc` also suggests that I should be using extra parenthesis, but
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I'm taking this as good comment :-)
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In addition to the above, the program has the following useful(?)
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@@ -2297,6 +2297,11 @@ like the original entry but with the two fixes.
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Cody made this more portable by changing the `void main` to `int main`.
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## [2000/rince](2000/rince/rince.c) ([README.md](2000/rince/README.md]))
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Cody added the [try.sh](2000/rince/try.sh) script.
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## [2000/thadgavin](2000/thadgavin/thadgavin.c) ([README.md](2000/thadgavin/README.md]))
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Cody fixed the code and added an appropriate make rule so that the SDL version
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