Directed Graph
Undirected graph can be connected or non-connected (if there is no path between two vertices)
Directed graph can be:
1. Unconnected (there can be edge between all vertices but because of edges, there is no path from some vertex u to some other other vertex v)
2. Strongly connected (from each (ordered) pair (u,v) there is a path from u and v And v and u.
3. Weakly connected (from each paid (u,v) there is a path either from u&v or from v&u or both.