Discuss what are static data members in class and how these are defined? How static functions are accessed?

Static data members in a class are those members that are common to all objects of that class. They are not tied to any specific object instance of that class and thus share the same value across all instances. They are defined within the class but outside any method, and they are declared with the keyword 'static'.

Here is how you can define a static data member in a class:

class MyClass {
public:
    static int myStaticVar;
};
int MyClass::myStaticVar = 0; // You need to initialize the static member outside the class.

In the above example, myStaticVar is a static data member of the class MyClass.

Static functions, on the other hand, can be called without instantiating the class. They can only access static data members of the class or other static member functions. They are accessed using the class name and the scope resolution operator ::.

Here is how you can define and access a static function:

class MyClass {
public:
    static int myStaticVar;
    static void myStaticFunction() {
        myStaticVar = 5;
    }
};
int MyClass::myStaticVar = 0;

// Accessing static function
int main() {
    MyClass::myStaticFunction();
    return 0;
}

In the above example, myStaticFunction is a static member function of the class MyClass. It is accessed without creating an object of MyClass.