Strange non-error (What DOES it do?)

[Absinthe]

I have been playing with some code generation and I ran across something that would seem like it should rais a compile error but it doesn't. However, it does not function as one might think either. What does it do? (See a2)

#include <iostream>
using namespace std;

class A {
public:  
  A() { cout << "Constructing" << endl;}
 ~A() { cout << "Destructing" << endl;}
};
int main (void) {
  A a1;               // <-- this works, constructs and destructs
  A a2();             // <-- this doesn't construct or destruct

  return 0;
}

Thanks,

-- Abs

[ne555]

A a2(); a function that returns an `A' object and receives no parameters.

[Absinthe]

I misunderstood what you said and posted incorrectly.

So what I am actually doing is creating a forward declaration, (prototype statement). So it is valid for the compiler, but surely it doesn't do what was expected :)

However, if I had a constructor such as:

class A {...
  A(int junkInteger) { //do something here...}
...}

I could declare:

   A anA(3);

In much the same way I could declare and instantiate integers:

  int iVal(7);

or strings:

  string myString("Hello, World!");

Seems an strange syntactical twist, no?

[Catfish3]

http://yosefk.com/c++fqa/ctors.html#fqa-10.2