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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
extern mod extra;
use std::int;
use std::io;
use std::os;
fn ack(m: int, n: int) -> int {
if m == 0 {
return n + 1
} else {
if n == 0 {
return ack(m - 1, 1);
} else {
return ack(m - 1, ack(m, n - 1));
}
}
}
fn main() {
let args = os::args();
let args = if os::getenv(~"RUST_BENCH").is_some() {
~[~"", ~"12"]
} else if args.len() <= 1u {
~[~"", ~"8"]
} else {
args
};
let n = int::from_str(args[1]).get();
io::println(fmt!("Ack(3,%d): %d\n", n, ack(3, n)));
}
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