| Topic: |
DEVELOP > c-Plus-Plus |
| User: |
"Luc Claustres" |
| Date: |
05 Dec 2004 03:06:35 PM |
| Object: |
Array size |
Is it possible to retrieve the number
of elements in a template array
dynamically allocated ?
void allocate()
{
int size = ...
T *pointer = new T[size];
}
void compute(T *pointer)
{
// Here I need the size but I can only access the pointer
}
Thanks.
.
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| User: "Buster" |
|
| Title: Re: Array size |
05 Dec 2004 09:52:37 PM |
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Luc Claustres wrote:
Is it possible to retrieve the number
of elements in a template array
dynamically allocated ?
In general no. Store the size too if you're going to need it.
void allocate()
{
int size = ...
T *pointer = new T[size];
Memory leak.
}
void compute(T *pointer)
{
// Here I need the size but I can only access the pointer
In fact you can't access either.
}
--
Regards,
Buster
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| User: "Virtual" |
|
| Title: Re: Array size |
06 Dec 2004 04:43:34 AM |
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|
Not really, but you could add another template parameter that comes
before anything that's deduced by the compiler. I've assumed function
templates for simplicity.
template<class T>
void allocate()
{
int size = T *pointer = new T[size];
compute<size>(T);
}
template<int U, class T>
void compute(T *pointer)
{
//do whatever you want here
}
Hope that helps.
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| User: "David Harmon" |
|
| Title: Re: Array size |
06 Dec 2004 08:02:55 PM |
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On 6 Dec 2004 02:43:34 -0800 in comp.lang.c++, "Virtual"
<justin.busby@gmail.com> wrote,
template<class T>
void allocate()
{
int size = T *pointer = new T[size];
Bogus.
compute<size>(T);
Also bogus, using a variable size for a template parameter.
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| User: "David Harmon" |
|
| Title: Re: Array size |
05 Dec 2004 08:52:57 PM |
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On Sun, 5 Dec 2004 22:06:35 +0100 in comp.lang.c++, "Luc Claustres"
<luc.claustres@numericable.fr> wrote,
Is it possible to retrieve the number
of elements in a template array
dynamically allocated ?
void allocate()
{
int size = ...
T *pointer = new T[size];
}
void compute(T *pointer)
{
// Here I need the size but I can only access the pointer
}
Use std::vector, then use the vector's size() member function to get
the size. Avoid roll-your-own substitutes for standard library
classes.
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