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::uninitialized_fill(&i[0], &i[3], val);
OR
std::uninitialized_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::uninitialized_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]

Michele Moccia wrote:

Simple newbie question:

I want to set an int array to value 5

int i[3];
int val=5;

<snip>

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

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

[Dietmar Kuehl]

Michele Moccia wrote:

I want to set an int array to value 5

int i[3];
int val=5;
std::uninitialized_fill(&i[0], &i[3], val);
OR
std::uninitialized_fill(i, i+3, val);
.... 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);
}
I need to pass as last iterator an out of index reference to completly
fill the array.

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:di***********@yahoo.com> <http://www.dietmar-kuehl.de/>
<http://www.eai-systems.com> - Efficient Artificial Intelligence

[JE]

Michele Moccia wrote:

Simple newbie question:

I want to set an int array to value 5

int i[3];
int val=5;

<snip>

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

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

[red floyd]

Dietmar Kuehl wrote:

[redacted
template <typename T, int size>
T* end(T(&array)[size]) { return array + T; } I assume you mean { return array + size; }

[Dietmar Kuehl]

red floyd wrote:

Dietmar Kuehl wrote:

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

I assume you mean { return array + size; }

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