std::uninitialized_fill

[Michele Moccia]

Simple newbie question:

I want to set an int array to value 5

int i[3];
int val=5;
std::uninitiali zed_fill(&i[0], &i[3], val);
OR
std::uninitiali zed_fill(i, i+3, val);

I need to pass as last iterator an out of index reference to completly fill
the array.
I think because std::uninitiali zed_fill do something like "while ( First !=
Last ) {...do something...}"
So my iterator will be incremented out of index? Is it dangerous?

Many thanks

Michele

[JE]

Re: std::uninitiali zed_fill

Michele Moccia wrote:[color=blue]
> Simple newbie question:
>
> I want to set an int array to value 5
>
> int i[3];
> int val=5;[/color]

<snip>

std::fill( i, i + sizeof(i)/sizeof(*i), val );

Leave uninitialized_f ill alone, unless you're writing allocators or
something...

[Dietmar Kuehl]

Re: std::uninitiali zed_fill

Michele Moccia wrote:[color=blue]
> I want to set an int array to value 5
>
> int i[3];
> int val=5;
> std::uninitiali zed_fill(&i[0], &i[3], val);
> OR
> std::uninitiali zed_fill(i, i+3, val);[/color]

.... or:

template <typename T, int size>
T* begin(T(&array)[size]) { return array; }
template <typename T, int size>
T* end(T(&array)[size]) { return array + T; }

int main()
{
int i[3];
std::fill(begin (i), end(i), 5);
}
[color=blue]
> I need to pass as last iterator an out of index reference to completly
> fill the array.[/color]

The pointer to the element one past the last array element is always
defined. Thus, it is safe to pass this pointer as an argument to a
function and, in fact, the STL algorithms take heavy advantage of
this features. Note, however, that you may not dereference this
pointer!
--
<mailto:dietmar _kuehl@yahoo.co m> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence

[JE]

Re: std::uninitiali zed_fill

Michele Moccia wrote:[color=blue]
> Simple newbie question:
>
> I want to set an int array to value 5
>
> int i[3];
> int val=5;[/color]

<snip>

std::fill( i, i + sizeof(i)/sizeof(*i), val );

Leave uninitialized_f ill alone, unless you're writing allocators or
something...

[red floyd]

Re: std::uninitiali zed_fill

Dietmar Kuehl wrote:[color=blue]
> [redacted
> template <typename T, int size>
> T* end(T(&array)[size]) { return array + T; }[/color]
I assume you mean { return array + size; }[color=blue]
>[/color]

[Dietmar Kuehl]

Re: std::uninitiali zed_fill

red floyd wrote:
[color=blue]
> Dietmar Kuehl wrote:[color=green]
>> [redacted
>> template <typename T, int size>
>> T* end(T(&array)[size]) { return array + T; }[/color]
> I assume you mean { return array + size; }[/color]

Yes, of course: I just typed the code without testing it...
--
<mailto:dietmar _kuehl@yahoo.co m> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence