CareerCup

Define a class with only protected constructors. This way the only thing that can construct the object is a child class.

define your destructor as pure virtual

class MakeAbs
{
public:
virtual void dummy()=0;
};
class MyClass:public MakeAbs
{};

As per m knowledge abstract class is the one, which have pure virtual function.

To define a function as abstract in C++ ( with the = 0; ) the function must be declared virtual as well to provide the ability to override the function in the child class. I can't find the line in the spec but, try it in VS and you will:
error C2253: 'Abstract::AbstractFunc' : pure specifier or abstract override specifier only allowed on virtual function

An abstract class has two features, cannot be created without being sub-classed and forces the child class to override a function.

My original suggestion above provided the first. Since the question does not want us to use virtual, then the second feature is not possible.

use key word "abstract".
abstract class CA
{
};

Virtual member functions are inherited. A class derived from an abstract base class will also be abstract unless you override each pure virtual function in the derived class.

for example: -

class base
{
	public:
	virtual void makevirtual()=0;
};

class derived:public base
{
};

here, derived has no virtual function and is still an abstract class

Make all the constructors(including compiler provided constructor i.e copy ctor) private and also provide protected static method through which can instantiate an objects

fd