std::iterator - Man Page

typedef _Distance difference_type
Distance between iterators is represented as this type.
typedef _Category iterator_category
One of the tag types.
typedef _Pointer pointer
This type represents a pointer-to-value_type.
typedef _Reference reference
This type represents a reference-to-value_type.
typedef _Tp value_type
The type pointedto"bytheiterator.

struct std::iterator< _Category, _Tp, _Distance, _Pointer, _Reference >"Common iterator class.

This class does nothing but define nested typedefs. Iterator classes can inherit from this class to save some work. The typedefs are then used in specializations and overloading.

In particular, there are no default implementations of requirements such as operator++ and the like. (How could there be?)

Distance between iterators is represented as this type.

One of the tag types.

This type represents a pointer-to-value_type.

This type represents a reference-to-value_type.

The type "pointed to" by the iterator.