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Brainfuck
(an exploration into the murky underworld of Computer Science and Programming Languages)
The language 'brainfuck' knows the following commands:
| Cmd | Effect | Equivalent in C |
|---|---|---|
| + | Increases element under pointer | array[p]++; |
| - | Decrases element under pointer | array[p]--; |
| > | Increases pointer | p++; |
| < | Decreases pointer | p--; |
| [ | Starts loop, counter under pointer | while(array[p]) { |
| ] | Indicates end of loop | } |
| . | Outputs ASCII code under pointer | putchar(array[p]); |
| , | Reads char and stores ASCII under ptr | array[p]=getchar(); |
All other characters are ignored. The 30000 array elements and p are being initialized to zero at the beginning. Now while this seems to be a pretty useless language, it can be proven that it can compute every solvable mathematical problem (if we ignore the array size limit and the executable size limit).
more? )
- the brainfuck archive → http://esoteric.sange.fi/brainfuck/
Actually, it's Turing-complete even if the executable size is limited to, say, half a K of source code. See http://www.hevanet.com/cristofd/brainfuck/brainfuck.html#turing and related pages.