C++11 member initializer list vs in-class initializer?

Question

What difference between these ways of initializing object member variables in C++11 ? Is there another way ? which way is better (performance) ?:

class any          


        

Answer 1

Both examples are equivalent.
Though only if the type is copyable or movable (check it for yourself) and NRVO is actually done (any halfway decent compiler will do it as a matter of course).

Though if you had many constructors and constructor-chaining were inappropriate, the first method would allow you not to repeat yourself.

Also, you can use that method to define aggregates with defaults different from aggregate-initialization for (some) members since C++14.