C / C++ / MFC

_AnsHUMAN_ wrote:

Moreover if we don't initialize the variables in the initializers list the compiler will have to do it for us and later on in the constructor this will be initialized again.

Philippe Mori wrote:

In standard C++, member without default constructor are not initialized to 0 automatically but are random.

class Any
{
  ....
  int var1 = 2; // This is an initializer.
  int var2;  // No initializer so set to default value (zero.)
  }

Philippe Mori wrote:

As far as I can tell, you have misunderstood the standard.

w-peuker wrote:

Some compilers initialize memory to zero. But for compatibility reasons, the C++ standard leaves (built-in type) members untouched (I don't know the latest one).

   class Any
   {
     ....
     int var1 = 2; // This is an initializer.
     int var2;  // No initializer so set to default value (zero.)
     }
<pre>

This happens regardless of how construction occurs.

Philippe Mori wrote:

See my answer above. You have misunderstood the standard.

class A
{
  //..
public:
  A();
  A(int);
  A& operator=(int);
};

class B
{
  A m_a;
public:
  B() { m_a = 3; /*second call, after A::A()*/}
  // B() : m_a(3) /*first and last call of A::A(int)*/ {}
};

They sought it with thimbles, they sought it with care;
They pursued it with forks and hope;
They threatened its life with a railway-share;
They charmed it with smiles and soap.