Neat Programming Tricks

Contents 1 References 1.1 Computer Alchemy 2 Meta-programming 3 ASCII Art 4 Music 5 Obfuscation

References

Computer Alchemy

Ken Thompson wrote an article called 'Reflections on Trusting Trust' in 1995 about the occult science of self-reproducing programs, and using them to hide trojan horses in source code that does not exist. This article made me remember my original fascination of computer science as a weird science that creates magic from secret spells and incantations. Read at your own discretion, the text is dangerous and may cause nightmares, hallucinations, or worse.

Meta-programming

Ruby quine:

b='puts "b=!#{b}!";puts b.gsub(33.chr,39.chr)'
puts "b='#{b}'";puts b.gsub(33.chr,39.chr)

Save to 'test.rb' and test with:

diff -s <(ruby test.rb) test.rb

ASCII Art

• See how to create beautiful ASCII Art with Ruby, Python or C++.
• Or perhaps use Python from the Vim editor to draw directly in your source code?

Music

This example shows how to play a tune on a Windows box using the winsound module for Python.

Obfuscation

This C program:

#include <stdio.h>
              main   (){char x[13]
              ;int  n=0;       x[5]
              =32;  for(
              ;n<4   ;n++
              ){x[      n*3+1+(n
              >2)]            =n+65
;x[           (n*2              +8)%
12]=          n+72              ;x[n
 *3+3        ]=(n   <3?(       n*4+
    2)%10+77:0)       ;}puts(x);}

Outputs:

JAKOB SCHMID

Here's the old and ugly version:

#include <stdio.h>
main() {char _[13]
;int    n=0; _[ 5]
=0x20;for (;n<4;n
++){_[n*3+1+(n>2)
]=n+65;_[ (n*2+8)%
12]=n+72;_[n*3+3]
 =(n<3?(n*4+2)%10+
 77:0);}puts (_);}