7f6
Subj : class member initialisation
To   : borland.public.cpp.borlandcpp
From : David Currie <curried@webspinning.com.au>
Date : Fri Oct 17 2003 12:56 am

Consider the following generalisation

class Apple
{
 private:
    int i1;   // data members
    int i2;
 public:
    Apple(int ii1,int ii2);  // Constructor

  // Destructors + methods etc
}

class FruitBox
{
  private:
    char c1;
    Apple a1;

  FruitBox (say) (char c);               // Constructor 1
  FruitBox(char c) : a1(value1,value2);  // Constructor 2 // example
  FruitBox(something s)                  // Constructor 3 // example

  // Destructors + methods etc
}

FruitBox::FruitBox(char c) // Constructor 1
{
  /* ... make a decision (perhaps based on char c)
         how to construct Apple a1   */

  Now how do i construct Apple a1 here ?
}

  ps :  I know using constructor 2 the compiler can construct Apple for
me

  but in general i dont know how to construct Apple until i am already
in the function

  1)  Apple a1 exists (its a part of the FruitBox object)

      can i construct Apple a1 here, if so how

        i know i can redesign methods here (say default Apple
constructor + setters)
        or say  Apple localApple(value1,value2);
                (this->)a1 = localApple;
           requiring operator= (assignment operator + copy methods etc)
           and to a degree this is duplicating effort.
        but in general this is not desired (for many reasons ...)


     how do i initialise it directly ?  is it initialisable by reference
?  this->a1(value1,value2) ?
     can a correct syntax construct Apple here ?
     if so what is it

  3) For that matter, consider constructor 3

     can constructor 3 (after some code sequence ...)  construct itself
using constructor 1 ?
     if so what is the appropriate syntax for one constructor to call
another constructor?

  4) Is all this a design limitation of C++?


  any responses would be greatly appreciated.
}

.

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