C++11 Difference in Constructors (Braces)

Question

I am quite new to C++ and have observed, that the following lines of code act differently

MyClass c1;
c1.do_work() //works
MyClass c2();
c2.do_work() //compi         


        

Answer 1

The second version

MyClass c2();

is a function declaration - see the most vexing parse and gotw.

The first case is default initialisation.

The last case, new to C++11, will call the default constructor, if there is one, since even though it looks like an initialiser list {}, it's empty.

Answer 2

Ways one and three call the default constructor.

MyClass c3{};

Is a new initialization syntax called uniform initialization. This is called default brace initialization. However:

MyClass c2();

Declares a function c2 which takes no parameters with the return type of MyClass.