Hi,

Often I come across situatation where I need to create array of
objects with parameterized constructors, there are alternative ways to
do this, but why can't it be a standard feature in C++.
some thing like this...
claas A
{
public:
  A(){}
  A(int v):_x(v),_y(v){}
  A(int v, int w):_x(v),_y(w){}
private:
  int _x;
  int _y;
};

int main()
{
  A *p1 = new A[3](5); //all objects have same value
  A *p2 = new A[3]{(5),(5,10),(20)}; //objects have different values
  return 0;
}

Is there any reason for not having some thing like this, or just
because of its complex to implement???

tia.
-Paul.

thanks Howard

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Hi,

Often I come across situatation where I need to create array of
objects with parameterized constructors, there are alternative ways to
do this, but why can't it be a standard feature in C++.
some thing like this...
class A
{
public:
  A(){}
  A(int v):_x(v),_y(v){}
  A(int v, int w):_x(v),_y(w){}
private:
  int _x;
  int _y;
};

int main()
{
  A *p1 = new A[3](5); //all objects have same value
  A *p2 = new A[3]{(5),(5,10),(20)}; //objects have different values
  return 0;
}

Is there any reason for not having some thing like this, or just
because of its complex to implement???

tia.
-Paul.

thanks Howard

---
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"Paul" <bgaloma@yahoo.com> wrote in message news:d8b1e3e6.0409051905.659554f0@posting.google.com...
| Hi,
|
| Often I come across situatation where I need to create array of
| objects with parameterized constructors, there are alternative ways to
| do this, but why can't it be a standard feature in C++.
|

|  A *p1 = new A[3](5); //all objects have same value
|   A *p2 = new A[3]{(5),(5,10),(20)}; //objects have different values
|   return 0;
| }
|
| Is there any reason for not having some thing like this,

The new boost.assign library (will be in the soon-to-be-release version of boost, see www.boost.org) allows you pretty much what you
want, for example,

std::vector<A> v = list_of<A>(5)(5,10)(20);

| or just
| because of its complex to implement???

There has to be compelling reasons for adding this to the standard. I don't think it will be hard to implement.

A library solution has these benefits:

1. no change to the language
2. its more flexible and can allow for stuff like

std::vector<A> v = list_of<A>(5).repeat( 10, A(20) )(5,10)(20)

3. most funcionality comes for free if the containers just have a constructor that takes
    two iterators.

br

Thorsten


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