Hands-on Rust

Trimming Input

The program’s output looks good on screen, but it contains a subtle bug. The string contains some extra characters representing the ENTER key. You can see this by replacing your last println! call with the following:

FirstStepsWithRust/treehouse_guestlist_problem/src/main.rs

println!("{:?}", name);

Replacing the {} placeholder with {:?} uses the debug placeholder. Any type that supports debug printing will print a detailed debugging dump of its contents, rather than just the value. If you run the program now, you can see the problem:

Hello, what's your name?
Herbert
"Herbert\r\n" (or "Herbert\n" on UNIX-based systems)

\r is a special character that means carriage return. On old printers, it returned the printhead ...