Rust and print

A little overview of the built-in print-like macros:

• print! to STDOUT.
• println! to STDOUT with a trailing newline.
• eprint! to STDERR.
• eprintln! to STDERR with a trailing newline.
• dbg! to STDERR with bells and whistles.
• format! returns formatted string. This is behind the printing macros.

#[allow(clippy::print_with_newline)]

fn main() {
    let fname = "Foo";
    let lname = "Bar";

    println!("{} {}", fname, lname);
    println!("{fname} {lname}");
    print!("{fname} {lname}\n");

    eprintln!("error in {} {}", fname, lname);
    eprint!("error in {} {}\n", fname, lname);

    let full_name = format!("{fname} {lname}");
    println!("{full_name}");
    dbg!(full_name);
}

Output:

Foo Bar
Foo Bar
Foo Bar
error in Foo Bar
error in Foo Bar
Foo Bar
[examples/intro/print.rs:14] full_name = "Foo Bar"

• print!
• println!
• eprint!
• eprintln!
• dbg!
• format!