Rust tree example

tree.rs

use std::{env,ffi,fs,io,path};

const DEFAULT_DEPTH: usize = 1024;

fn main() -> io::Result<()> {
    let max_depth: usize = env::args()
        .nth(1)
        .and_then(|s| s.parse().ok())
        .unwrap_or(DEFAULT_DEPTH);

    println!("Directory tree. Max depth = {}", max_depth);

    // Stack with PathBuf and depth
    let mut stack: Vec<(path::PathBuf, usize)> = vec![(path::PathBuf::from("."), 0)];

    while let Some((path, depth)) = stack.pop() {
        let name = path.file_name()
            .unwrap_or(ffi::OsStr::new(".")) // Root path has no file name?
            .to_string_lossy();

        print!("{}{}", "  ".repeat(depth), name);

        if path.is_dir() {
            println!("/");
            if depth < max_depth {
                for entry in fs::read_dir(&path)? {
                    let child = entry?.path();
                    stack.push((child, depth + 1));
                }
            }
        } else {
            println!()
        }
    }

    Ok(())
}