Cody Boone Ferguson
22e483723c
Instead of code blocks the bug / (mis)features statuses are quoted rather than in a code block. In the case that there is more than one a line break was added at the end of all but the last one. A bug status was renamed to be slightly more correct (maybe more than one was renamed for the same purpose but at least one was). The bug statuses in the quotes are now bold to let them stand out better.
100 lines
2.8 KiB
Markdown
100 lines
2.8 KiB
Markdown
## To build:
|
|
|
|
``` <!---sh-->
|
|
make
|
|
```
|
|
|
|
|
|
### Bugs and (Mis)features:
|
|
|
|
The current status of this entry is:
|
|
|
|
> **STATUS: INABIAF - please DO NOT fix**
|
|
|
|
For more detailed information see [2011/borsanyi in bugs.html](../../bugs.html#2011_borsanyi).
|
|
|
|
|
|
## To use:
|
|
|
|
``` <!---sh-->
|
|
./borsanyi < some_data_file
|
|
```
|
|
|
|
|
|
## Try:
|
|
|
|
``` <!---sh-->
|
|
./try.sh
|
|
```
|
|
|
|
|
|
## Judges' remarks:
|
|
|
|
This is a nice quick [histogram](https://en.wikipedia.org/wiki/Histogram)
|
|
plotter. A useful utility when you need to look at the distribution of some
|
|
data.
|
|
|
|
|
|
### Challenges:
|
|
|
|
You can modify the number of histogram
|
|
[bins](https://en.wikipedia.org/wiki/Data_binning) and the scaling of the
|
|
histogram by editing the source. Try to find them!
|
|
|
|
If you look at the source you will notice that the usual array of
|
|
histogram bins is missing. The source contains no arrays and it does not
|
|
use `malloc(3)` or `alloca(3)`. How does it build the histogram?
|
|
|
|
While the input does not need to be sorted, the histogram output is sorted.
|
|
How does it put the data into buckets? Why does it `fork(2)` 22 times?
|
|
|
|
|
|
## Author's remarks:
|
|
|
|
This small piece of program is meant to be a useful tool, when
|
|
there are some data around and you need a quick glance at the
|
|
histogram. I am all too often logged in to a remote machine with
|
|
slow X connection, and a terminal-based program would be of
|
|
great help.
|
|
|
|
|
|
### Limitations
|
|
|
|
* I optimized the output for the data I had around, you might want to adjust
|
|
for your needs. For a great excess of data points the program will crash
|
|
(depending on the available stack).
|
|
* Giving too few (distinct) points can also cause crash (or division by zero).
|
|
* The program expects plain numbers separated by white spaces.
|
|
* ASCII is assumed.
|
|
* Some POSIX-like system is assumed (`fork()` and `wait(NULL)` are used).
|
|
* Do not give any arguments to the program.
|
|
* Could rounding errors cause the omission of the highest bin? There might be
|
|
empty bins at the edges.
|
|
|
|
|
|
### Obfuscation
|
|
|
|
* The program follows a rather unconventional approach to the task
|
|
of histogram building. The usual array of integers (for the histogram
|
|
bins) is missing entirely. The data are read once, the range is determined,
|
|
but the data points are not put in any array. Yet they are remembered,
|
|
and each of them is put into its own bin afterwards. But where are the bins?
|
|
* I tried to use as few keywords as possible, hence there are no loops.
|
|
* Multi-process approach for optimal use of resources.
|
|
* Some bin size obfuscation.
|
|
|
|
|
|
<!--
|
|
|
|
Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
|
|
|
|
You are free to share and adapt this file under the terms of this license:
|
|
|
|
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
|
|
|
|
For more information, see:
|
|
|
|
https://creativecommons.org/licenses/by-sa/4.0/
|
|
|
|
-->
|