Method get

code/chapter07/bst.rs:172–193

获取值，和查找流程相似

(&self, key: &T)

    // 获取值，和查找流程相似
    fn get(&self, key: &T) -> Option<&U> {
        match &self.key {
            None => None,
            Some(k) => {
                match k.cmp(key) {
                    Ordering::Equal => self.val.as_ref(),
                    Ordering::Greater => {
                        match &self.left {
                            None => None,
                            Some(node) => node.get(key),
                        }
                    },
                    Ordering::Less => {
                        match &self.right {
                            None => None,
                            Some(node) => node.get(key),
                        }
                    },
                }
            },
        }
    }
}

fn main() {