Most performant way of converting int to string

[Daniel Kozák via Digitalmars-d-learn]

V Tue, 22 Dec 2015 20:52:07 +0000
rumbu via Digitalmars-d-learn <digitalmars-d-learn at puremagic.com>
napsáno:

> On Tuesday, 22 December 2015 at 19:45:46 UTC, Daniel Kozák wrote:
> > V Tue, 22 Dec 2015 18:11:24 +0000
> > rumbu via Digitalmars-d-learn 
> > <digitalmars-d-learn at puremagic.com>
> > napsáno:
> >  
> >> On Tuesday, 22 December 2015 at 17:15:27 UTC, Andrew Chapman 
> >> wrote:  
> >> > Sorry if this is a silly question but is the to! method from 
> >> > the conv library the most efficient way of converting an 
> >> > integer value to a string?
> >> >
> >> > e.g.
> >> > string s = to!string(100);
> >> >
> >> > I'm seeing a pretty dramatic slow down in my code when I use 
> >> > a conversion like this (when looped over 10 million 
> >> > iterations for benchmarking).
> >> >
> >> > Cheers!  
> >> 
> >> Converting numbers to string involves the most expensive known 
> >> two operations : division and modulus by 10.  
> >
> > No, IIRC few months or maybe years I have optimize this so it 
> > does not use division and modulus  
> 
> It's using division and modulus, as expected:
> 
> https://github.com/D-Programming-Language/phobos/blob/master/std/conv.d#L5529
> 
> If the compiler is smart enough, maybe it will replace this by 
> well known multiplication trick.

Yes compiler is smart enought so it will not use division and modulus
as I say before :)