Static members (C++ only)

Class members can be declared using the storage class specifier static in the class member list. Only one copy of the static member is shared by all objects of a class in a program. When you declare an object of a class having a static member, the static member is not part of the class object.

A typical use of static members is for recording data common to all objects of a class. For example, you can use a static data member as a counter to store the number of objects of a particular class type that are created. Each time a new object is created, this static data member can be incremented to keep track of the total number of objects.

You access a static member by qualifying the class name using the :: (scope resolution) operator. In the following example, you can refer to the static member f() of class type X as X::f() even if no object of type X is ever declared:

struct X {
  static int f();
};

int main() {
  X::f();
}