Improve examples

Author: korthaj

example_dfs_test.go

@@ -64,8 +64,7 @@ func (d *DFSData) dfsVisit(g graph.Iterator, v int) {
 	d.Finish[v] = d.Time
 }
 
-// An implementation of depth-first search
-// demonstrating how to use this package.
+// Show how to use this package by implementing a complete depth-first search.
 func Example_dFS() {
 	// Build a small directed graph:
 	//

examples_test.go

@@ -5,7 +5,7 @@ import (
 	"github.com/yourbasic/graph"
 )
 
-// How to iterate over the edges of a graph.
+// Build a plain graph and visit all of its edges.
 func Example_basics() {
 	// Build a graph with four vertices and four undirected edges.
 	// (Each of these edges are, in fact, represented by two directed