use std::collections::BTreeMap;
use std::cmp::Ordering;
use std::ops::Bound::{Included, Excluded};

#[derive( Debug)]
struct FloatWrapper(f32);

impl Eq for FloatWrapper { }

impl PartialEq for FloatWrapper {
    fn eq(&self, other: &Self) -> bool {
        (self.0 - other.0).abs() < 1.17549435e-36f32
    }
}

impl Ord for FloatWrapper {
    fn cmp(&self, other: &Self) -> Ordering {
        if (self.0 - other.0).abs() < 1.17549435e-36f32 {
            Ordering::Equal
        } else if self.0 - other.0 > 0.0 {
            Ordering::Greater
        } else if self.0 - other.0 < 0.0 {
            Ordering::Less
        } else {
            Ordering::Equal
        }

    }
}

impl PartialOrd for FloatWrapper {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

fn main() {

    let mut ww = BTreeMap::new();
    ww.insert(FloatWrapper(1.0), "one");
    ww.insert(FloatWrapper(2.0), "two");
    ww.insert(FloatWrapper(3.0), "three");
    ww.insert(FloatWrapper(4.0), "three");
    let rez : Vec<&str> = ww.range((Included(&FloatWrapper(1.5)),(Excluded(&FloatWrapper(5.0)) )))
        .take(1)
        .map(|(_,&v)|v)
        .collect();


   println!("{:?}",rez)

}