what keyword is used to specify that a data member is a class data member

The keyword used to specify that a data member is a class data member shared by all instances of the class in C++ is static. When a data member is declared with the static keyword inside a class, it means that this member belongs to the class itself rather than to any particular object instance. There is only one copy of this static data member shared among all objects of the class

. In summary:

• Use static before a data member declaration inside a class to make it a class data member (shared by all instances).
• Non-static data members belong to individual objects.

Example:

cpp

class MyClass {
public:
    static int sharedValue;  // static data member, shared by all objects
    int individualValue;     // non-static data member, unique to each object
};

This is the standard way in C++ to specify a class data member.