Aggregate initialization with regular constructor

Question

Suppose I have the following class:

class dog
{
    public:
    int age;
    int bun;
};

Now this statement

dog d = {12,5}

would initialize age to 12 and bun to 5

Now if the class above has a parameter-less constructor the above statement initialization does not work. I would appreciate it if someone could explain why that happens?

Kerrek SB · Accepted Answer · 2014-04-21 00:13:26Z

4

The syntax dog d = { 12, 5 }; is aggregate initialization when the class dog is an aggregate. A user-provided constructor prevents a class from being an aggregate; cf. C++11 8.5.1/1:

An aggregate is an array or a class (Clause 9) with no user-provided constructors (12.1), no brace-or-equal-initializers for non-static data members (9.2), no private or protected non-static data members (Clause 11), no base classes (Clause 10), and no virtual functions (10.3).

(I believe that the next revision of C++ will permit brace-or-equals initializers in aggregates.)

edited Apr 21, 2014 at 0:13

answered Apr 20, 2014 at 22:15

Kerrek SB

480k96 gold badges904 silver badges1.1k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Rajeshwar Over a year ago

Thanks. That explained it. Marked as answer

Collectives™ on Stack Overflow

Aggregate initialization with regular constructor

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related