public/subjects/brain_fuck

brain_fuck

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 exercise 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.

For receiving arguments from the command line you should use something like:

fn main() {
    let args: Vec<String> = std::env::args().collect();

    brain_fuck(&args[1]);
}

Usage

$ cargo run "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."
Hello World!
$ cargo run "+++++[>++++[>++++H>+++++i<<-]>>>++\n<<<<-]>>--------.>+++++.>."
Hi
$ cargo run "++++++++++[>++++++++++>++++++++++>++++++++++<<<-]>---.>--.>-.>++++++++++."
abc