Class edge_iterator

Graph/UndirectedGraph.h:193–260

Iterate through edges. */

/** Iterate through edges. */
class edge_iterator
	: public std::iterator<std::input_iterator_tag, edge_descriptor>
{
	void nextVertex()
	{
		vertex_iterator vlast = m_g->vertices().second;
		for (; m_vit != vlast; ++m_vit) {
			std::pair<adjacency_iterator, adjacency_iterator>
				adj = m_g->adjacent_vertices(*m_vit);
			/*
			 * Since each edge exists as both (u, v) and
			 * (v, u), require `adj.first >= *m_vit` to visit only
			 * one of the two possible forms.
			 */
			if (adj.first != adj.second && *adj.first >= *m_vit) {
				m_eit = adj.first;
				return;
			}
		}
		// Set m_eit to a known value.
		static const adjacency_iterator s_eitNULL;
		m_eit = s_eitNULL;
	}

  public:
	edge_iterator() { }
	edge_iterator(const UndirectedGraph* g, const vertex_iterator& vit)
		: m_g(g), m_vit(vit)
	{
		nextVertex();
	}

	edge_descriptor operator*() const
	{
		return edge_descriptor(*m_vit, *m_eit);
	}

	bool operator==(const edge_iterator& it) const
	{
		return m_vit == it.m_vit && m_eit == it.m_eit;
	}

	bool operator!=(const edge_iterator& it) const
	{
		return !(*this == it);
	}

	edge_iterator& operator++()
	{
		if (++m_eit == m_g->adjacent_vertices(*m_vit).second) {
			++m_vit;
			nextVertex();
		}
		return *this;
	}

	edge_iterator operator++(int)
	{