[#BloombergLP-bslstl-TreeIterator]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::TreeIterator
:relfileprefix: ../../
:mrdocs:

This class provides an STL‐conforming bidirectional iterator over the ordered `bslalg::RbTreeNode` objects in a binary tree (see section [24.2.6 bidirectional.iterators]of the C++11 standard). A `TreeIterator` provides access to values of the parameterized `VALUE`, over a binary tree composed of nodes of the parameterized `NODE` (which must derive from `bslalg::RbTreeNode`). The parameterized `DIFFERENCE_TYPE` determines the standard required `difference_type` of the iterator, without requiring access to the allocator‐traits for the node. The behavior of the `operator*` method is undefined unless the iterator is at a valid position in the tree (i.e., not the `end`) and the referenced element has not been removed since the iterator was constructed. `NODE` must derives from `bslalg::RbTreeNode`, and contains a `value` method that returns a reference providing modifiable access to a type that is convertible to the parameterized `VALUE` (e.g., a `bslstl::TreeNode` object).

== Synopsis

Declared in `<bslstl_treeiterator.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class VALUE,
    class NODE,
    class DIFFERENCE_TYPE>
class TreeIterator;
----

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/TreeIterator/difference_type.adoc[`difference_type`] 
| The difference type for this iterator.
| xref:BloombergLP/bslstl/TreeIterator/iterator_category.adoc[`iterator_category`] 
| The STL iterator category tag for this iterator.
| xref:BloombergLP/bslstl/TreeIterator/pointer.adoc[`pointer`] 
| Pointer type for the value referred to by this iterator.
| xref:BloombergLP/bslstl/TreeIterator/reference.adoc[`reference`] 
| Standard iterator defined types [24.4.2].
| xref:BloombergLP/bslstl/TreeIterator/value_type.adoc[`value_type`] 
| The value type referred to by this iterator.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/TreeIterator/2constructor-0a.adoc[`TreeIterator`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bslstl/TreeIterator/node.adoc[`node`] 
| Return the address of the non‐modifiable tree node at which this iterator is positioned, or 0 if this iterator is not at a valid position in the tree. Note that this method is an implementation detail and is not part of the C++ standard.
| xref:BloombergLP/bslstl/TreeIterator/operator_star.adoc[`operator*`] 
| Return a reference providing modifiable access to the value (of the parameterized `VALUE`) of the element at which this iterator is positioned. The behavior is undefined unless this iterator is at a valid position in the tree.
| xref:BloombergLP/bslstl/TreeIterator/operator_inc.adoc[`operator++`] 
| Move this iterator to the next element in the tree and return a reference providing modifiable access to this iterator. The behavior is undefined unless the iterator refers to an element in the tree.
| xref:BloombergLP/bslstl/TreeIterator/operator_dec.adoc[`operator‐‐`] 
| Move this iterator to the previous element in the tree and return a reference providing modifiable access to this iterator. The behavior is undefined unless the iterator refers to the past‐the‐end address or the non‐leftmost element in the tree.
| xref:BloombergLP/bslstl/TreeIterator/operator_ptr.adoc[`operator‐>`] 
| Return the address of the value (of the parameterized `VALUE`) of the element at which this iterator is positioned. The behavior is undefined unless this iterator is at a valid position in the tree.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `BloombergLP::bslstl::TreeIterator`
| This class provides an STL‐conforming bidirectional iterator over the ordered `bslalg::RbTreeNode` objects in a binary tree (see section [24.2.6 bidirectional.iterators]of the C++11 standard). A `TreeIterator` provides access to values of the parameterized `VALUE`, over a binary tree composed of nodes of the parameterized `NODE` (which must derive from `bslalg::RbTreeNode`). The parameterized `DIFFERENCE_TYPE` determines the standard required `difference_type` of the iterator, without requiring access to the allocator‐traits for the node. The behavior of the `operator*` method is undefined unless the iterator is at a valid position in the tree (i.e., not the `end`) and the referenced element has not been removed since the iterator was constructed. `NODE` must derives from `bslalg::RbTreeNode`, and contains a `value` method that returns a reference providing modifiable access to a type that is convertible to the parameterized `VALUE` (e.g., a `bslstl::TreeNode` object).
| `xref:BloombergLP/bslstl/operator_eq-02.adoc[BloombergLP::bslstl::operator==]`
| Return whether the specified iterators refer to the same tree node.
|===

== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/operator_inc-02.adoc[`operator++`]
| Move the specified `iter` to the next element in the tree and return the value of `iter` prior to this call. The behavior is undefined unless the iterator refers to an element in the tree.
| xref:BloombergLP/bslstl/operator_dec-03.adoc[`operator‐‐`]
| Move the specified `iter` to the previous element in the tree and return the value of `iter` prior to this call. The behavior is undefined unless the iterator refers to the past‐the‐end or the non‐leftmost element in the tree.
| xref:BloombergLP/bslstl/operator_eq-0c0.adoc[`operator==`]
| Return `true` if the specified `lhs` and the specified `rhs` iterators have the same value and `false` otherwise. Two iterators have the same value if they refer to the same position in the same tree, or if both iterators are at an invalid position in the tree (i.e., the `end` of the tree, or the default constructed value).
|===


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