fn f_to_c(f: f64) -> f64 {
    (f - 32.0) * (5.0 / 9.0)
}

fn c_to_f(c: f64) -> f64 {
    c * (9.0 / 5.0) + 32.0
}

fn main() {

    // f to c / c to f
    let f1 = 0.0;
    let f2 = 32.0;
    let f3 = 80.0;
    let f4 = 212.0;
    let c1 = f_to_c(f1);
    let c2 = f_to_c(f2);
    let c3 = f_to_c(f3);
    let c4 = f_to_c(f4);

    println!("{f1}f {c1}c");
    println!("{f2}f {c2}c");
    println!("{f3}f {c3}c");
    println!("{f4}f {c4}c");

    let f5 = c_to_f(100.0);
    println!("100c = {f5}f");
    // fib
    //
    let mut x1 = 0;
    let mut x2 = 1;
    let mut temp = 0;
    while x1 < 2000 {
        println!("x: {x1}");
        temp = x2;
        x2 = x1 + x2;
        x1 = temp;
    }
}