我是一个新手，当它涉及到生 rust ，我一直得到这个错误，老实说，我不知道发生了什么事。我正在做一个华氏到摄氏度，反之亦然。这是我的代码：

use std::io;

fn main() {
    let mut choose = String::new();
    println!("Choose between Celsius To Fahrenheit [1] or Fahrenheit to Celsius [2],\
    please introduce a corrected value (integer)");
    io::stdin()
        .read_line(&mut choose)
        .expect("Failed to read!");
    // Careful with the trim, cuz it's removing all characters and it causes and error that basically, closes the CMD
    // Carriage return BE CAREFUL MAN!
    if choose.trim() == "1" {
        println!("Please, Introduce a value ");
        io::stdin().read_line(&mut choose).expect("Please, enter an integer");
        let choose: i32 = choose.trim().parse().expect("Jjaanokapasao");
        ctof(choose);
    } else if choose.trim() == "2" {
        println!("Please, Introduce a value");
        io::stdin().read_line(&mut choose).expect("Please, enter an integer");
        let choose: usize = choose.trim_end().parse().expect("Failed to convert to i32");
        ftpc(choose);
    }
}

fn ctof(c: i32) {
    let celsius_to_fahrenheit: i32 = (c * (9 / 5)) + 32;
    println!("Here is your conversion: {celsius_to_fahrenheit}")
}

fn ftpc(f: usize) {
    let fahrenheit_to_celsius: usize = (f-32) * (5 / 9);
    println!("Here is your conversion: {fahrenheit_to_celsius}")
}

'''