Exception classes with throwing copy-constructors

Dear all,
I need some help understanding the mchanism (as described in the
standard) of the exceptions.
Let's consider an example

#include <iostream>
//exception class, whose copy constructor throws on second and further
invocations
struct Exc
{
   Exc(){}
   Exc(Exc const &)
   {
      static int x = 0;
      if(x)
         throw 0;
      ++x;
   }
};

int main()
{
   try
   {
      throw Exc();
   }
   catch(Exc e)
   {
      std::cout << "Exc\n";
      Exc e1(e);
   }
   catch(int)
   {
      std::cout << "int\n";
   }
}

The questions are:
1. What should the output of this progam be, if defined
2. What whould the output of this progam be, if defined, if we were to
catch Exc by reference
3. What whould the output of this progam be, if defined, if we were to
catch Exc by reference, but Exc's copy-constructor ha\\had changed so
that it ALWAYS throws 0.
4. What whould the output of this progam be, if defined, if we were to
catch Exc by value, but Exc's copy-constructor ha\\had changed so that
it ALWAYS throws 0.

And, of course, each of 4 questions is foolowed by a "and why?" :)
Thank you in advance,
Armen Tsirunyan