#[derive(Clone,Copy,Debug,Hash)]
pub struct Ratio<Num,Den>{
	pub(crate)num:Num,
	pub(crate)den:Den,
}
//this trait is like a constructor for Ratio
pub trait DeferredDiv<Rhs=Self>{
	type Output;
	fn deferred_div(self,rhs:Rhs)->Self::Output;
}