<p>what is the best way to put a container class or a some other class inside a class as private or a public member?</p>

<p>Requirements:</p>

<p>1.Vector&lt; someclass> inside my class</p>

<p>2.Add and count of vector is needed interface</p>

Whether a member is declared Private or Public depends entirely on your application. Could you give some more detail?
One important point to remember when declaring your member is that if you provide a "getter" to retrieve it, then you are no longer encapsulating that object. Instead, it can be good to write wrapper methods exposing only the functionality you wish to expose.
For example, with a Vector member, you might write an AddItem and Clear method, if that's all the functionality you wish to expose.