const confusion

const confusion

I would like to make an array will will only be used for one purpose
and whose members are constant.
E.g. double arr[3] = { 0., 1., 2. };

I'd like arr to always point to this array and the entries to always
be these values. What is the right syntax for const in this situation?

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spasmous
04-03-08 03:07 AM

Re: const confusion

spasmous said:

> I would like to make an array will will only be used for one purpose
> and whose members are constant.
> E.g. double arr[3] = { 0., 1., 2. };
>
> I'd like arr to always point to this array and the entries to always
> be these values. What is the right syntax for const in this situation?

arr isn't a pointer, so it will never point to the array. It *is* the
array, insofar as it is the array's name. It is not a modifiable lvalue,
so you can't change it to be associated with some other array.

If by "always" you mean for the entire lifetime of the program, you can do
this by moving it to file scope, or by static-qualifying it, or both.

To make sure the values can't (legally) change, simply use const:

const double arr[3] = { 0., 1., 2. };

This defines and initialises an array of three const doubles. Strangely, so
would this:

double const arr[3] = { 0., 1., 2. };  /* same as before! */

--
Richard Heathfield <http://www.cpax.org.uk>
Email: -http://www. +rjh@
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Richard Heathfield
04-03-08 03:07 AM