challenge: implement the max function

[Frits van Bommel]

Lionello Lunesu wrote:
> "Andrei Alexandrescu (See Website For Email)" 
> <SeeWebsiteForEmail at erdani.org> wrote in message 
> news:45B3B243.2010103 at erdani.org...
>> Here's a simple challenge: implement the max function. Requirements:
>>
>> a) generic
>> b) efficient
>> c) preserve lvalueness when possible such that one can write e.g.
>>
>> max(arr[0], arr[1]) *= 0.9;
> 
> ...when would that be useful? And, what happens if arr[0]==arr[1] ?

Can't immediately think up an example of usefulness, but what presumably 
happens if they're equal is that one of them gets reduced by 10% (and 
rounded to the accuracy of typeof(arr[0])).