dangling reference

[Nick Keighley]

I saw this in some code I'm maintaining. Is it a bad idea?
class T
{
public #:
T () i_mem(0)
{ }

T (T2 &t2) i_mem(0), t2_ref (t2)
{ }
private:
int i_mem;
T2 &t2_ref;
}

This is from memory and the real code compiles so any syntax errors
are my fault. It also had destructors, copy constructors etc.

What bothered me was the apparently uninitialised reference in the
default constructor.

If it were a pointer then would it be initialised to NULL by default?

But a reference *must* reference something?
--
Nick Keighley

[Marcin Kalicinski]

> class T

{
public #:
T () i_mem(0)
{ }

T (T2 &t2) i_mem(0), t2_ref (t2)
{ }
private:
int i_mem;
T2 &t2_ref;
}

This is from memory and the real code compiles so any syntax errors
are my fault. It also had destructors, copy constructors etc.

This code should not compile, because the all member references must be
initialized in constructor initializer list. What might be happening in your
case (you say it compiles) is that class T is actually a template
parametrized on T2 type. If so, you might not get error unless default
constructor is actually used. I don't know if this is mandated by the
standard, but at least Visual C++ .NET behaves this way.

cheers,
Marcin