What causes "Error Getting your input" in coding-horror/basic-computer-games?

Replace .expect() with .unwrap_or_default() — an empty string won't equal 'YES', so the game correctly prints 'SO LONG' and exits

coding-horror/basic-computer-games · error

Error Getting your input

Error message

Error Getting your input

What it means

In 47_Hi-Lo, after each jackpot round the game asks 'PLAY AGAIN (YES OR NO)?' and reads the response via io::stdin().read_line(&mut tocontinue).expect("Error Getting your input"). The response is compared case-insensitively to 'YES' to decide whether to continue. The .expect() panics on stdin I/O failure.

Source

Thrown at 47_Hi-Lo/rust/src/main.rs:63

                println!("YOUR GUESS IS TOO LOW.\n");
            } else {
                println!("YOUR GUESS IS TOO HIGH.\n");
            }

            // if 6 tries are over make total jackpot amount to zero
            if i == 5 {
                total = 0;
                println!(
                    "YOU BLEW IT...TOO BAD...THE NUMBER WAS {}\n",
                    jackpot_amount
                );
            }
        }
        println!("PLAY AGAIN (YES OR NO)?");
        let mut tocontinue = String::new();
        io::stdin()
            .read_line(&mut tocontinue)
            .expect("Error Getting your input");
        let tocontinue = tocontinue.trim().to_ascii_uppercase();
        if tocontinue.eq("YES") {
            println!("\n");
            continue;
        } else {
            println!("\nSO LONG.  HOPE YOU ENJOYED YOURSELF!!!\n");
            break;
        }
    }
}

View on GitHub (pinned to 5301155192)

Solutions

Replace .expect() with .unwrap_or_default() — an empty string won't equal 'YES', so the game correctly prints 'SO LONG' and exits
Use if read_line(...).is_err() to break the outer loop
Return early from the function on Err

Example fix

// before
let mut tocontinue = String::new();
io::stdin()
    .read_line(&mut tocontinue)
    .expect("Error Getting your input");
let tocontinue = tocontinue.trim().to_ascii_uppercase();

// after
let mut tocontinue = String::new();
let _ = io::stdin().read_line(&mut tocontinue);
let tocontinue = tocontinue.trim().to_ascii_uppercase();

Defensive patterns

Strategy: fallback

Try / catch

let mut tocontinue = String::new();
let _ = io::stdin().read_line(&mut tocontinue);
// empty string != "YES", so the game prints 'SO LONG' and exits,
// which is the correct response to EOF at this prompt

Prevention

For yes/no prompts where non-yes already means exit, I/O failure should produce the same exit — use let _ = instead of .expect()
Recognize that EOF at a 'play again?' prompt is the user's way of saying 'no more' — treat it accordingly
Avoid .expect() on the final input in a game session where the natural response to EOF is 'stop playing'

When it happens

Trigger: The game finishes a round and prompts to continue, but stdin is at EOF or the read fails. A non-'YES' answer already triggers the 'SO LONG' exit, so EOF should logically behave the same way.

Common situations: Piped input that ends after a game round, pressing Ctrl+D at the play-again prompt, or automated tests that stop feeding input after one game.

Related errors

AI-assisted analysis of coding-horror/basic-computer-games@5301155192 (2026-08-13). Data as JSON: /api/errors/a0f1ca3bc781d5ca. Report an issue: GitHub.