What are static class members?

Static class members are data and functions that are associated with the class itself, rather than with the objects of the class. Static data members are often referred to as class data, and static member functions are often referred to as class services or class methods. In case of static functions the static keyword is applied to the function declaration and not to the function definition.
If a class has a static data member, there is only one copy of that data even if there are many instances of the class. This is like a global variable shared among all the class instances. One can use the static variable or call the static method using the class name.
Example:
class ShoppingCart
{
private:
static int items;
public:
static int getItems();
static void incItemCount();
};