a data member that has no default contructor?

**symbiote** · 03-27-2009

hi Guys,

i basicly want a class that has no default constructor as a data member of another class. something like this:

Code:

class A
{
public:
	A( int x );
};

class B //other class
{
private:
	A objectA;
public:
	B( int x );
};
A B::objectA = A( 0 );

my question: can it be done?
i would appreciate any help

**edoceo** · 03-27-2009

Code:

class A {
  public:
    A (int x) {};
};

class B {
  public:
    B (int x) : m_A (x) {}

  private:
    A m_A;
};

int
main (int argc, char *argv[])
{
  B foo (2);

  return 0;
}

**cpjust** · 03-27-2009

Are you asking how to prevent people from using the default constructor?
Simple, make the default constructor private.

**laserlight** · 03-27-2009

Originally Posted by cpjust

Are you asking how to prevent people from using the default constructor?

I think symbiote is asking how to initialise a member variable of a type that has no default constructor, in which case edoceo's suggestion of using the constructor initialisation list is correct.

**cpjust** · 03-27-2009

Originally Posted by laserlight

I think symbiote is asking how to initialise a member variable of a type that has no default constructor, in which case edoceo's suggestion of using the constructor initialisation list is correct.

Ah yes, after re-reading it, now that makes sense.

**symbiote** · 03-29-2009

thanks for the replies.
i almost forgot i asked this question.
i wanted a class that must to be initialized.
thanks edoceo. that's exactly what i was looking for.

Greetings

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