Edge may also have visited flags set and cleared. Compare edge, based on labels. When edge is directed, vtx1 specifies source. When undirected, order of vertices is unimportant. Label on edge is any type, and may be null.
Edge is initially unvisited.
The label associated with the edge. When edge is directed, vtx1 specifies source. When undirected, order of vertices is unimportant. Label on edge is any type, and may be null. Edge is initially unvisited.