fn double(x: Int) -> Int {
    x * 2
}

fn add(a: Int, b: Int) -> Int {
    a + b
}

fn main() {
    let x = 21
    let result = double(x)
    println("double({x}) = {result}")

    let sum = add(10, 32)
    println("add(10, 32) = {sum}")

    println("sqrt(144) = ... (built-in math)")
    println("All done!")
}
