How to use correctly the crate text_io?

May 8, 2024

I have a small problem with a crate:
This code works:

fn main() {
    println!("Celsius to farenheit");
    print!("Insert Celsius: ");
    let celsius: f32 = read!();
    println!("Celsius to Farenheit is: {}", cel_to_far(celsius));
}

But if I use what is in the manual of text_io:

fn main() {
    println!("Celsius to farenheit");
    let celsius: f32 = read!("Insert Celsius: {}!");
    println!("Celsius to Farenheit is: {}", cel_to_far(celsius));
}

It panics:

Celsius to farenheit
6
thread 'main' panicked at src/main.rs:4:24:
called `Result::unwrap()` on an `Err` value: UnexpectedValue(73, Some(54))
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

This doesn’t and I think I’m following the correct instructions:

>Solution :

Both snippets are not equivalent!

The first one prints Insert Celsius: then reads an integer, the second one will read Insert Celsius: then an integer and then an ! meaning you have to type all that, it doesn’t print it. That is the second one expects you to type all of Insert Celsius: 123!