Standard Template Library Programmer's Guide

None.

[1] It is not required that an Output Iterator inherit from the base output_iterator . It is, however, required that the function iterator_category be defined for every Output Iterator. (Or, if you are using the iterator_traits mechanism, that iterator_traits is properly specialized for every Output Iterator.) Since it is defined for the base output_iterator , the easiest way to ensure that it defined for a new type is to derive that class from output_iterator and rely on the derived-to-base standard conversion of function arguments.

The Iterator Tags overview, iterator_traits , iterator_category , value_type , distance_type , input_iterator , forward_iterator , bidirectional_iterator , random_access_iterator

Category: iterators

Component type: type

Forward_iterator is an iterator base class: it is intended that an iterator that is a model of Forward Iterator, and whose value type and distance type are T and Distance , may be defined by inheriting from forward_iterator [1]. Forward_iterator is entirely empty: it has no member functions, member variables, or nested types. It exists solely to simplify the definition of the functions iterator_category , distance_type , and value_type .

class my_forward_iterator : public forward_iterator {

…

};

This declares my_forward_iterator to be a Forward Iterator whose value type is double and whose distance type is ptrdiff_t . If Iter is an object of class my_forward_iterator , then iterator_category(Iter) will return forward_iterator_tag() , value_type(Iter) will return (double*)0 , and distance_type(Iter) will return (ptrdiff_t*)0 .

Defined in the standard header iterator, and in the nonstandard backward-compatibility header iterator.h. This class is no longer part of the C++ standard, although it was present in early drafts of the standard. It is retained in this implementation for backward compatibility.

Assignable

None

The distance type must be a signed integral type.

None.

None.

None.

[1] It is not required that a Forward Iterator inherit from the base forward_iterator . It is, however, required that the functions iterator_category , distance_type , and value_type be defined for every Forward Iterator. (Or, if you are using the iterator_traits mechanism, that iterator_traits is properly specialized for every Forward Iterator.) Since those functions are defined for the base forward_iterator , the easiest way to ensure that are defined for a new type is to derive that class from forward_iterator and rely on the derived-to-base standard conversion of function arguments.

The Iterator Tags overview, iterator_traits , iterator_category , value_type , distance_type , input_iterator , output_iterator , bidirectional_iterator , random_access_iterator

Category: iterators

Component type: type

Bidirectional_iterator is an iterator base class: it is intended that an iterator that is a model of Bidirectional Iterator, and whose value type and distance type are T and Distance , may be defined by inheriting from bidirectional_iterator [1]. Bidirectional_iterator is entirely empty: it has no member functions, member variables, or nested types. It exists solely to simplify the definition of the functions iterator_category , distance_type , and value_type .

class my_bidirectional_iterator : public bidirectional_iterator {

…

};

This declares my_bidirectional_iterator to be a Bidirectional Iterator whose value type is double and whose distance type is ptrdiff_t . If Iter is an object of class my_bidirectional_iterator , then iterator_category(Iter) will return bidirectional_iterator_tag() , value_type(Iter) will return (double*)0 , and distance_type(Iter) will return (ptrdiff_t*)0 .

Defined in the standard header iterator, and in the nonstandard backward-compatibility header iterator.h. This class is no longer part of the C++ standard, although it was present in early drafts of the standard. It is retained in this implementation for backward compatibility.

Assignable

None

The distance type must be a signed integral type.

None.

None.

None.

[1] It is not required that a Bidirectional Iterator inherit from the base bidirectional_iterator . It is, however, required that the functions iterator_category , distance_type , and value_type be defined for every Bidirectional Iterator. (Or, if you are using the iterator_traits mechanism, that iterator_traits is properly specialized for every Bidirectional Iterator.) Since those functions are defined for the base bidirectional_iterator , the easiest way to ensure that are defined for a new type is to derive that class from bidirectional_iterator and rely on the derived-to-base standard conversion of function arguments.

The Iterator Tags overview, iterator_traits , iterator_category , value_type , distance_type , input_iterator , output_iterator , forward_iterator , random_access_iterator