# Inverse Adjacency Iterator Adaptor

Defined in header
boost/graph/adjacency_iterator.hpp
The inverse adjacency iterator adaptor transforms an
`in_edge_iterator` into an inverse adjacency iterator. That is, it
takes an iterator that traverses over edges, and creates an iterator
that traverses over the *source* vertices of those edges.

## Synopsis

namespace boost {
template <class Graph, class VertexDescriptor, class InEdgeIter>
class inv_adjacency_iterator_generator {
public:
typedef iterator_adaptor<...> type;
};
}

### Example

The following is an example of how to use the
`inv_adjacency_iterator_generator` class.

#include <boost/graph/adjacency_iterator.hpp>
class my_graph {
// ...
typedef ... in_edge_iterator;
typedef ... vertex_descriptor;
typedef boost::inv_adjacency_iterator_generator<my_graph, vertex_descriptor, in_edge_iterator>::type inv_adjacency_iterator;
// ...
};

### Template Parameters

Parameter | Description |

`Graph` |
The graph type, which must model Incidence Graph. |

`VertexDescriptor` |
This must be the same type as
`graph_traits<Graph>::vertex_descriptor`. The reason why
this is a template parameter is that the primary use of
`inv_adjacency_iterator_generator` is *inside* the
definition of the graph class, and in that context we can not use
`graph_traits` on the not yet fully defined graph class.
**Default:** `graph_traits<Graph>::vertex_descriptor` |

`InEdgeIter` |
This must be the same type as
`graph_traits<Graph>::in_edge_iterator`.
**Default:** `graph_traits<Graph>::in_edge_iterator
` |

### Model of

The inverse adjacency iterator adaptor (the type
`inv_adjacency_iterator_generator<...>::type`) is a model of Multi-Pass Input Iterator
.
### Members

The inverse adjacency iterator type implements the member functions and
operators required of the Random Access Iterator
concept, except that the `reference` type is the same as the `value_type`
so `operator*()` returns by-value. In addition it has the following constructor:
inv_adjacency_iterator_generator::type(const InEdgeIter& it, const Graph* g)

Revised 19 Aug 2001

© Copyright Jeremy Siek 2000. Permission to copy, use,
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