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brainfuck: A few corrections

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Mathias Bynens 2013-09-04 10:24:15 +02:00
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@ -1,11 +1,12 @@
--- ---
language: brainfuck language: brainfuck
contributors: contributors:
- ["Prajit Ramachandran", "http://prajitr.github.io"] - ["Prajit Ramachandran", "http://prajitr.github.io/"]
- ["Mathias Bynens", "http://mathiasbynens.be/"]
--- ---
Brainfuck is an extremely minimal programming language (just 8 commands) and Brainfuck (not capitalized except at the start of a sentence) is an extremely
is Turing complete. minimal Turing-complete programming language with just 8 commands.
``` ```
Any character not "><+-.,[]" (excluding quotation marks) is ignored. Any character not "><+-.,[]" (excluding quotation marks) is ignored.
@ -27,7 +28,7 @@ There are eight commands:
[ and ] form a while loop. Obviously, they must be balanced. [ and ] form a while loop. Obviously, they must be balanced.
Let's look at some basic Brainfuck programs. Let's look at some basic brainfuck programs.
++++++ [ > ++++++++++ < - ] > +++++ . ++++++ [ > ++++++++++ < - ] > +++++ .
@ -45,21 +46,18 @@ print cell #2's value. 65 is 'A' in ASCII, so 'A' is printed to the terminal.
, [ > + < - ] > . , [ > + < - ] > .
This program reads a character from the user input, copies the character into This program reads a character from the user input and copies the character into
another cell, and prints out the same character. cell #1. Then we start a loop. Move to cell #2, increment the value at cell #2,
move back to cell #1, and decrement the value at cell #1. This continues on
, reads in a character from the user into cell #1. Then we start a loop. Move until cell #1 is 0, and cell #2 holds cell #1's old value. Because we're on
to cell #2, increment the value at cell #2, move back to cell #1, and decrement cell #1 at the end of the loop, move to cell #2, and then print out the value
the value at cell #1. This continues on until cell #1 is 0, and cell #2 holds in ASCII.
cell #1's old value. Because we're on cell #1 at the end of the loop, move to
cell #2, and then print out the value in ASCII.
Also keep in mind that the spaces are purely for readibility purposes. You Also keep in mind that the spaces are purely for readibility purposes. You
could just as easily write it as could just as easily write it as:
,[>+<-]>. ,[>+<-]>.
Try and figure out what this program does: Try and figure out what this program does:
,>,< [ > [ >+ >+ << -] >> [- << + >>] <<< -] >> ,>,< [ > [ >+ >+ << -] >> [- << + >>] <<< -] >>
@ -73,7 +71,7 @@ problem: at the end of the inner loop, cell #2 is zero. To solve this problem,
we also increment cell #4, and then recopy cell #4 into cell #2. we also increment cell #4, and then recopy cell #4 into cell #2.
``` ```
And that's Brainfuck. Not that hard, eh? For fun, you can write your own And that's brainfuck. Not that hard, eh? For fun, you can write your own
Brainfuck programs, or you can write a Brainfuck interpreter in another brainfuck programs, or you can write a brainfuck interpreter in another
language. The interpreter is fairly simple to implement, but if you're a language. The interpreter is fairly simple to implement, but if you're a
masochist, trying writing a Brainfuck interpreter... in Brainfuck. masochist, try writing a brainfuck interpreter… in brainfuck.