Newbie Arrays

Newbie Arrays

[Ronald Ayoub]

Right now I'm learning about multidimensional arrays and arrays of arrays.
I want to do something similiar to this with multidimensional arrays:

    for I in V'first..V'last loop
        for J in V(I)'first..V(I)'last loop
            V(I)(J) := I * J;
        end loop;
    end loop;

but I can't see how to use the 'first and 'last attributes with
multidimensional arrays. In C there is no real difference between
an array of arrays and a multidimensional arrays except syntactically.
Are array of arrays more commonly used by Ada programers.

Thanks.

Ron

Re: Newbie Arrays

[Gautier]

(...)
> but I can't see how to use the 'first and 'last attributes with
> multidimensional arrays. 

'first(1) 'first(2) etc.

-- 
Gautier

--------
http://members.xoom.com/gdemont/

Re: Newbie Arrays

[Matthew Heaney]

In article <7p1555$bf0$1@dailyplanet.wam.umd.edu> , rayoub@wam.umd.edu 
(Ronald Ayoub) wrote:

> Right now I'm learning about multidimensional arrays and arrays of arrays.
> I want to do something similiar to this with multidimensional arrays:
>
>     for I in V'first..V'last loop
>         for J in V(I)'first..V(I)'last loop
>             V(I)(J) := I * J;
>         end loop;
>     end loop;

  for I in V'Range (1) loop
    for J in V'Range (2) loop
       V (I) (J) := I * J;
    end loop;
  end loop;


> but I can't see how to use the 'first and 'last attributes with
> multidimensional arrays.

Like the 'Range attribute, the 'First and 'Last attributes take a parameter
specifying which dimension.

But never say

  for I in V'First (1) .. V'Last (1) loop ...;

Instead, say

  for I in V'Range (1) loop ...;



> In C there is no real difference between
> an array of arrays and a multidimensional arrays except syntactically.

Not quite.  In C, there is no such thing as a multidimensional array.  All
arrays are really arrays-of-arrays.

Read Expert C Programming, by Peter van der Linden, for a good discussion of
this.


> Are array of arrays more commonly used by Ada programers.

In Ada, we have both arrays-of-arrays, and true multidimensional arrays.
Which is used depends on the nature of the problem.