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Typedef of a fixed length array

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  Typedef of a fixed length array "raphfrk@gmail.com" <raphfrk@gmail.com> - 2011-06-30 08:41 -0700
    Re: Typedef of a fixed length array jt@toerring.de (Jens Thoms Toerring) - 2011-06-30 16:15 +0000
      Re: Typedef of a fixed length array James Kuyper <jameskuyper@verizon.net> - 2011-07-01 06:50 -0400

#7301 — Typedef of a fixed length array

Is there a way to define a typedef to be an array of fixed length?

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#7304

raphfrk@gmail.com <raphfrk@gmail.com> wrote:
> Is there a way to define a typedef to be an array of fixed length?

Did you consider

typedef int array_of_10_ints[ 10 ];

int main( ) {
    array_of_10_ints x;
    size_t i;
    for ( i = 0; i < sizeof x / sizeof *x; i++ )
        x[ i ] = i;
...

The real challenge would be to typedef an array of variable
length, I guess;-)
                            Regards, Jens
-- 
  \   Jens Thoms Toerring  ___      jt@toerring.de
   \__________________________      http://toerring.de

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#7352

On 06/30/2011 12:15 PM, Jens Thoms Toerring wrote:
> raphfrk@gmail.com <raphfrk@gmail.com> wrote:
>> Is there a way to define a typedef to be an array of fixed length?
> 
> Did you consider
> 
> typedef int array_of_10_ints[ 10 ];
> 
> int main( ) {
>     array_of_10_ints x;
>     size_t i;
>     for ( i = 0; i < sizeof x / sizeof *x; i++ )
>         x[ i ] = i;
> ...
> 
> The real challenge would be to typedef an array of variable
> length, I guess;-)

It's not much of a challenge, but the typedef can only have block scope
(6.7.7p2).

(6.7.7p8):
EXAMPLE 5 If a typedef name denotes a variable length array type, the
length of the array is fixed at the time the typedef name is defined,
not each time it is used:
	void copyt(int n)
	{
	    typedef int B[n]; // B is n ints, n evaluated now
	    n += 1;
	    B a; // ais n ints, n without += 1
	    int b[n]; // a and b are different sizes
	    for (int i = 1; i < n; i++)
	        a[i-1] = b[i];
	}

-- 
James Kuyper

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