What's the difference between new MyClass and new MyClass()

Question

Possible Duplicate:
Difference between A* pA = new A; and A* pA = new A();
Variable initialization (pointer and value)

Assuming that MyClass has a default constructor, what's the difference between

MyClass *mc = new MyClass;

and

MyClass *mc = new MyClass();

Assuming that you mean a user-declared default constructor, in this case there is no difference. — CB Bailey, Sep 06 '12 at 08:42

score 6 · Accepted Answer · answered Sep 06 '12 at 08:39

6

Assuming that MyClass has a default constructor

2 extra characters in the code.

If the class is a POD type (not your case), the latter will perform value-initialization.

answered Sep 06 '12 at 08:39

Luchian Grigore

Thanks for you reply. Is it another trap in C++ ? – Alan Sep 06 '12 at 10:20
I just come up with another question, if the two sentences are basically the same thing.Why C++ accept this ambiguity ? Is it some kind of compromise to the compatibility？ Can anyone provide any reference ? – Alan Sep 07 '12 at 01:54
Sorry, I mean two different syntax，have the same meaning.Of course in my case. – Alan Sep 07 '12 at 09:13
@Alan they have the same meaning in some cases (as stated in the answer). – Luchian Grigore Sep 07 '12 at 09:16
:) thanks again. C++ is killing me. – Alan Sep 07 '12 at 09:20

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