/*
** $Id: insane.cc 619 2007-03-23 02:18:15Z phf $
**
** Some crazy stuff, strictly for your entertainment. :-)
*/

#include <iostream>
#include <string>

using std::cout;
using std::endl;

// Remember how in C there was a difference between a function
// defined with () and a function defined with (void)? Right,
// the former could be called with *any* argument list, while
// the latter could only be called with the empty argument list.
// In C++ that's apparently fixed, at least for methods, so ()
// is now the same as (void), 100%.

class One
{
public:
  One() {
    cout << "Default constructor!" << endl;
  }
  One(int i) {
    cout << "Integer constructor!" << endl; i = 1;
  }
};

class Two
{
public:
  Two(void) {
    cout << "Void constructor!" << endl;
  }
  Two(int i) {
    cout << "Integer constructor!" << endl; i = 1;
  }
};

// If you were sufficiently C-damaged, you might expect that
// you can overload () versus (void), but of course you can't.
// Funny thing about it is the error message. Comment out the
// class Three below and try yourself. :-)

/*
class Three
{
public:
  Three() {
    cout << "Default constructor!" << endl;
  }
  Three(void) {
    cout << "Void constructor!" << endl;
  }
};
*/

// BTW, you'll get the same result with two () constructors
// and two (void) constructors, showing that the two notations
// are identical in C++. Good, it makes sense that way, it's
// just that C is different and less sensible.

int main(void)
{
  // Alright, so when we make objects of these classes, we'd
  // expect the default constructor to get called. And it does,
  // in both cases.

  cout << "--- one ---" << endl;
  One one;
  cout << "--- two ---" << endl;
  Two two;

  // Step back for a second. Let's say we want both of these to
  // be initialized from an integer. Of course we'd write this:

  cout << "--- eins ---" << endl;
  One eins(1);
  cout << "--- zwei ---" << endl;
  Two zwei(2);

  // And of course the integer constructor gets called in both
  // cases. Hmm, so we can have no parenthesis or parenthesis
  // with an argument. What about just parenthesis with nothing
  // in between? Shouldn't that call the default constructor as
  // well?

  cout << "--- argh ---" << endl;
  One argh();
  cout << "--- barf ---" << endl;
  Two barf();

  // No output? None? What the heck is going on? Try to figure
  // it out yourself. If you get stuck, comment out the code
  // below and compile again, you should get it then. Yes, the
  // syntax of C and C++ is *really* horrible. :-)

/*
  cout << "----------" << endl;
  cout << sizeof(One) << endl;
  cout << sizeof(one) << endl;
  cout << sizeof(argh) << endl;
  cout << sizeof(Two) << endl;
  cout << sizeof(two) << endl;
  cout << sizeof(barf) << endl;
*/
}