Re: Copying rows in a two dimensional array.

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Peter C. Chapin wrote:
> 
> type Matrix is array(Positive range <>, Positive range <>) of Floating_Type;
> 
> I need to exchange two rows in this array. What I'd like to do is something
> along these lines:
> 
>    Temp_Array      := A(I, 1 .. Size);
>    A(I, 1 .. Size) := A(K, 1 .. Size);
>    A(K, 1 .. Size) := Temp_Array;
> 
> The compiler (GNAT GPL 2009) has a problem with this syntax and, after looking
> into it some, I think that's because slicing only works for one dimensional
> arrays. Fair enough.

That's correct: slicing is only defined for one-D arrays.

> So I thought, "Perhaps A needs to be an array of arrays."
> 
> type Matrix is array(Positive range <>) of WHAT_EXACTLY?

Row_Vector?

> Apparently the component type of an array needs to be fully constrained (which
> again makes sense) yet I don't know the size I'll want to use at the point
> where this type is declared.

Correct again: array components must be definite.

I'm not aware of a solution other than the brute force approach.

-- 
Jeff Carter
"Gentlemen, you can't fight in here. This is the War Room!"
Dr. Strangelove
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