Strange behavior in constructor

Question

I have a class made up of several fields, and I have several constructors. I also have a constructor that doesn't take any parameters, but when I try to use it:

int main {
    A a;
}

The compiler generates an error, while if I use it like this:

int main {
    A a();
}

It's ok. What's that?

Thank you

Answer 1

The first main uses A's default constructor. The second one declares a function that takes no parameters and returns an A by value, which probably isn't what you intend.

So what does the definition of A look like and what is the error that the compiler generates?

Oh, and you need to provide a parameter list in the declaration of main: int main() { //... , not int main { //...