graphs with the standard-gauge line you started on or any of the lines that could be reached from your line here' another situation in which you might need to find all the vertices reachable from specified vertex imagine that you're designing printed circuit boardlike the ones inside your computer (open it up and take look!various components-mostly integrated circuits (ics)--are placed on the boardwith pins from the ics protruding through holes in the board the ics are soldered in placeand their pins are electrically connected to other pins by traces--thin metal lines applied to the surface of the circuit boardas shown in figure (noyou don' need to worry about the details of this figure pins traces figure pins and traces on circuit board in grapheach pin might be represented by vertexand each trace by an edge on circuit board there are many electrical circuits that aren' connected to each otherso the graph is by no means connected one during the design processthereforeit may be genuinely useful to create graph and use it to find which pins are connected to the same electrical circuit assume that you've created such graph now you need an algorithm that provides systematic way to start at specified vertex and then move along edges to other vertices in such way thatwhen it' doneyou are guaranteed that it has visited every vertex that' connected to the starting vertex hereas it did in "binary trees,where we discussed binary treesvisit means to perform some operation on the vertexsuch as displaying it there are two common approaches to searching graphdepth-first search (dfsand breadth-first search (bfsboth will eventually reach all connected vertices the depth-first search is implemented with stackwhereas the breadth-first search is