In msdn, the explain of the class keyword is:
The class keyword declares a class type or defines an object of a class type.
class [tag [: base-list ]] { member-list } [declarators]; [ class ] tag declarators;
The elements of a class definition are as follows:
i want to know how to use the tag to declare a class's type.
Thanks!

how to declares a class type?
timdilbert
Just choose a valid name:
class CDog
{
public:
void Bark();
};
This name is used to define/create a object og this type:
void Foo()
{
CDog dog;
dog.Bark();
}