use std::fs::OpenOptions;

use std::io::prelude::*;
use std::io::BufWriter;
use std::io::stdout;

use std::path::PathBuf;

fn main() {
    // let output_file = Some(PathBuf::from("output.txt"));
    let output_file: Option<PathBuf> = None;
    let backend: Box<dyn Write> = match output_file {
        Some(p) => Box::new(OpenOptions::new().write(true).create(true).open(&p).unwrap()),
        None => Box::new(stdout()),
    };
    let mut buffer = BufWriter::new(backend);

    write!(&mut buffer, "Hello {}", "world").unwrap();
}