Function inorder

publication/code/chapter08/binary_tree.rs:298–304

(bt: Link<T>)

}

fn inorder<T: Clone + Ord + ToString + Debug>(bt: Link<T>) {
    if !bt.is_none() {
        inorder(bt.as_ref().unwrap().get_left());
        println!("key: {:?}", bt.as_ref().unwrap().get_key());
        inorder(bt.as_ref().unwrap().get_right());
    }
}

fn postorder<T: Clone + Ord + ToString + Debug>(bt: Link<T>) {
    if !bt.is_none() {