Converting between Fahrenheit and Celsius using Rust

degree_converter.rs

use std::io;

fn main() {
    println!("Hello there user,");
    loop{
        println!("Which units will you be converting from F or C? (type q to quit):");
        
        let mut unit = String::new();
        io::stdin().read_line(&mut unit)
            .expect("Could not read input.");
        //println!("You chose {}", unit);
        
        if unit.trim() == String::from("q"){
            break;
        };

        println!("Enter the number of degrees you want to convert from in numbers:");
        
        let mut val = String::new();
        io::stdin().read_line(&mut val)
            .expect("Could not read input.");

        let val_int: isize = match val.trim().parse() {
            Ok(num) => num,
            Err(_) => continue
        };

        let f = String::from("F");
        let c = String::from("C");
        let output = if unit.trim() == f {
            f_to_c(val_int)
        }else if unit.trim() == c{
            c_to_f(val_int)
        } else {
            5
        };
        
        println!("{:?}", output);
    }
    println!("See you later!")
}

fn f_to_c(deg_val: isize) -> isize {
    let converted = deg_val - 32;
    let converted = converted * 5;
    let converted = converted / 9;
    converted
}

fn c_to_f(deg_val: isize) -> isize{
    let converted = deg_val * 9;
    let converted = converted / 5;
    let converted = converted + 32;
    converted
}