Default Initialization Versus Zero Initialization

Question

I cannot understand the behavior of gcc 4.8.1 or Visual Studio 2015 with respect to default initialization versus value initialization.

It doesn\'t help that I\'m tr

Answer 1

Foo foo;

This default-initializes foo, and since Foo's default constructor is trivial, it effectively doesn't initialize it at all, so foo._bar can hold any value (including 0).

Foo()

This value-initializes the temporary object, which in case of trivial default constructor means zero-initialization, so Foo()._bar is equal to 0.