/* DepthFirst: depth-first traversal of a graph.

 
Pre:  The graph G has been created.
Post: The function Visit has been performed at each vertex of G in
depth-first order.
Uses: Function Traverse produces the recursive depth-first order.
 */
void DepthFirst(Graph G, void (*Visit)(Vertex))
{
    Boolean visited[MAXVERTEX];
    Vertex v;

    for (all v in G)
        visited[v] = FALSE;
    for (all v in G)
        if (!visited[v])
            Traverse(v, Visit);
}
 
/* Traverse: recursive traversal of a graph

 
Pre:  v is a vertex of the graph G.
Post: The depth-first traversal, using function Visit, has been completed
for v and for all vertices adjacent to v.
Uses: Traverse recursively.
 */
void Traverse(Vertex v, void (*Visit)(Vertex))
{
    Vertex w;

    visited[v] = TRUE;
    Visit(v);
    for (all w adjacent to v)
        if (!visited[w])
            Traverse(w, Visit);
}