CODEWITHSUNDEEP
c++c++11
Rajeshwar
Rajeshwar

Reputation: 11651

Aggregate initialization with regular constructor

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?

Upvotes: 1

Views: 87

Answers (1)

Kerrek SB
Kerrek SB

Reputation: 476950

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.)

Upvotes: 4

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