public/subjects/brainfuck

brainfuck

Instructions

Write a Brainfuck interpreter program. The source code will be given as first parameter. The code will always be valid, with less than 4096 operations. Brainfuck is a minimalist language. It consists of an array of bytes (in this exercice 2048 bytes) all initialized with zero, and with a pointer to its first byte.

Every operator consists of a single character :

• '>' increment the pointer
• '<' decrement the pointer
• '+' increment the pointed byte
• '-' decrement the pointed byte
• '.' print the pointed byte on standard output
• '[' go to the matching ']' if the pointed byte is 0 (loop start)
• ']' go to the matching '[' if the pointed byte is not 0 (loop end)

Any other character is a comment.

Usage

$ go run . "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>." | cat -e
Hello World!$
$ go run . "+++++[>++++[>++++H>+++++i<<-]>>>++\n<<<<-]>>--------.>+++++.>." | cat -e
Hi$
$ go run . "++++++++++[>++++++++++>++++++++++>++++++++++<<<-]>---.>--.>-.>++++++++++." | cat -e
abc$
$ go run .
$