TITLE: New definition of default constructor


PROBLEM: scsr91@csc.liv.ac.uk (Mr. J.A. Coyne)

class compound  {
   basic * array; // pointer to class basic
public:
   compound(); // class constructor function
};

compound::compound()  { array = new basic[10]; }

class basic {
    int * vector;
public:
      basic(int =5) ;
};

basic::basic(int size)  { vector = new int[size]; }

The error message I recieve is  : default arguments for constructor for array
of class basic(2005)



RESPONSE: steve@taumet.com (Steve Clamage)

This is an area where the language has changed.  An array of objects
with a constructor require the "default constructor".  It used to be
that the "default constructor" was one which had no parameters, and a
constructor with all parameters defaulted was not a substitute.  The
newer language rule is that the "default constructor" is one which
does not require arguments, meaning that your code is now legal.

The cfront 2.1 compiler followed the old rule.  A workaround is to
make two constructors:

    basic()	    { vector = new int[5]; }
    basic(int size) { vector = new int[size]; }