CODEWITHSUNDEEP
c++arraysclass
JCSB
JCSB

Reputation: 385

array class member with different size for each class instance

I would like to have a class that contains an array member, but the constructor lets me set the size of an array member.

Is this doable? I do not thing I need dynamic allocation, since once the class instances are created, there is no need for the array to change size, it is just that each class instance will have a different size.

Upvotes: 0

Views: 369

Answers (1)

UniversE
UniversE

Reputation: 2507

Despite several comments suggest that this would be impossible, it is actually not impossible.

The simplest way, of course, is to use an indirection and allocate the array during construction just the normal way (with a = new type[size] and calling delete[] a - not delete a - in the destructor).

But if for some reason you really do not want to have the array data being allocated separately from your object, you can use placement-new to construct your object into a pre-allocated buffer that is large enough to contain all your elements. This avoids a separate allocation for your array and you can still have dynamic size.

I would not recommend using this technique, though, unless you really have a demanding use case for it.

Upvotes: 1

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