RE: [Dev-C++] Use of const qualifier

[Scott W. <se...@al...>]

Thanks for the reply--very helpful.  You might know the answer to a related
question. . .

I have a math-intensive subroutine that is called millions of times (yes,
millions) by a numerical algorithm.  Currently, all of the variables in this
subroutine are of automatic extent.  Would there be any efficiency gained by
instead giving them static extent?  Each call to the subroutine is
independent so retaining values across calls is not an issue.  Rather, this
is a question of how the memory access itself is handled.

Thanks.
Scott


-----Original Message-----
From: Abhijit Shylanath [mailto:mu...@gm...]
Sent: Thursday, October 31, 2002 5:30 PM
To: se...@al...; Dev-C++ Mailing List
Subject: Re: [Dev-C++] Use of const qualifier


> where myfunc uses the values of x and the array members of y but doesn't
> change them.  Is there then an efficiency (speed) to be gained by instead
> declaring:
>
> double myfunc(const double x, const double *y)?

More than speed, the const qualifier is for debugging. It prevents the
programmer from inadvertently changing the values of certain variables. Some
new optimizing compilers also use it to align memory more efficiently.

___________________________________________________________

Abhijit Shylanath

E-mail:   mu...@gm... || ibr...@bi...
Web-site: http://mudeth.tripod.com/