delete vs delete[] [duplicate]

This question already has answers here: 开发者_如何学运维 Closed 12 years ago.

Possible Duplicate:

( POD )freeing memory : is delete[] equal to delete ?

When I was taught C++, this was a long time ago. I was told to never use delete but delete[] as performing delete[] on a single object will be equivalent to delete. Knowing not to trust teachers too much I wonder, Is this true?

Is there ever a reason to call delete instead of delete[]?

I've scanned the possibly related questions in SO, but haven't found any clear answer.

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From the standard (5.3.5/2) :

In the first alternative (delete object), the value of the operand of delete shall be a pointer to a non-array object or a pointer to a sub-object (1.8) representing a base class of such an object (clause 10). If not, the behavior is undefined.

In the second alternative (delete array), the value of the operand of delete shall be the pointer value which resulted from a previous array new-expression. If not, the behavior is undefined.

So no : they are in no way equivalent !

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delete [] is "vector delete" and corresponds to vector new, i.e. new[].

You must use the matching pair of allocators. E.g. malloc/free, new/delete, new[]/delete[], else you get undefined behavior.

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No! you call delete[] when you allocate with new[], otherwise you call delete.

What teacher told you leads to undefined behaviour and, if you are lucky, an application crash.

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delete is used to delete a single object, while delete[] is used to delete an array of objects. Check this link for more info.