MyDataConatiner is kind of facade to MyData.
I Dont want to allow other classes to create Mydata .
it has some logic of lazy instantiation that I want to keep in MyDataConatiner .
thought about something like private ctor with friend class , but I am not sure.
or is it something with one of factory design patterns
One way is to make MyDataContainer a friend of MyData as shown below:
class MyData
{
//befriend MyDataContainer so that MyDataContainer can create object of type MyData
friend class MyDataContainer;
//private converting ctor that can be used by MyDataContainer but not normal users
MyData(int)
{
}
};
class MyDataContainer
{
public:
//add method(s) for creating MyData object
//other code here
};