4 files changed, 23 insertions, 18 deletions

diff --git a/Graph.cs b/Graph.cs
index 8521bd4..10381f1 100644
--- a/Graph.cs
+++ b/Graph.cs
@@ -14,19 +14,23 @@ namespace Graph
             Vertices = vertices;
         }
 
-        // Indexer for accessing vertex with id of index 
+        // indexer for accessing vertex with id of index 
         public Vertex<T> this[int index] { get => Vertices.Find(vertex => vertex.Id == index); }
 
+        // create virtex if needed, then add the edge to it's edges list
         public void AddEdge(Edge<T> edge)
         {
+            // look for existing vertex, and use it if found
             Vertex<T> vertex = Vertices.Find(u => u.Id == edge.U);
 
             if (vertex == null)
             {
+                // if not found, create a new vertex
                 Vertices.Add(vertex = new Vertex<T>(edge.U));
                 vertex = Vertices[Vertices.Count - 1];
             }
-
+            
+            // add the edge to the new/found vertex
             vertex.Edges.Add(edge);
         }
 
diff --git a/IO/FileReader.cs b/IO/FileReader.cs
index 12aa12b..a207be2 100644
--- a/IO/FileReader.cs
+++ b/IO/FileReader.cs
@@ -2,7 +2,8 @@ using System.IO;
 using Graph.Interfaces;
 
 namespace Graph.IO
-{    
+{
+    // class for reading from file using IFileReader (i.e. Dependancy injection for unit testing)
     public class FileReader : IFileReader
     {
         public string[] Lines { get; }
diff --git a/IO/FileWriter.cs b/IO/FileWriter.cs
index 7e10f62..846b759 100644
--- a/IO/FileWriter.cs
+++ b/IO/FileWriter.cs
@@ -1,9 +1,9 @@
-using System;
 using System.IO;
 using Graph.Interfaces;
 
 namespace Graph.IO
 {
+    // class for writing to file using IFileWriter (i.e. Dependancy injection for unit testing)
     public class FileWriter : IFileWriter
     {
         string FilePath { get; }
diff --git a/IO/GraphFile.cs b/IO/GraphFile.cs
index 8562170..dc1d851 100644
--- a/IO/GraphFile.cs
+++ b/IO/GraphFile.cs
@@ -1,5 +1,3 @@
-using System.Collections.Generic;
-using System.Linq;
 using System.Text.RegularExpressions;
 using Graph.Interfaces;
 
@@ -7,6 +5,7 @@ namespace Graph.IO
 {
     public static class GraphFile
     {
+        // read a graph from file using IFileReader (i.e. Dependancy injection for unit testing)
         public static Graph<double> Read(IFileReader reader)
         {
             string[] lines = reader.Lines;
@@ -42,31 +41,32 @@ namespace Graph.IO
             return graph;
         }
 
+        // write a graph to file using IFileWriter (i.e. Dependancy injection for unit testing)
         public static void Print(Graph<double> graph, IFileWriter writer)
         {
+            // create array of strings with a size equal to vertices
             string[] lines = new string[graph.Vertices.Count];
+            
+            // add each vertex to it's parents output line 
             graph.Vertices.ForEach(vertex =>
             {
+                // do nothing if it has no parent
                 if (vertex.Parent == null)
                     return;
 
+                // needed due to making vertex.Parent nullable
                 int parent = vertex.Parent.GetValueOrDefault();
-                
-                lines[parent] ??= $"{parent}";
-                lines[vertex.Id] ??= $"{vertex.Id}";
 
+                // for vertex & parent, create string if not already
+                lines[vertex.Id] ??= $"{vertex.Id}";
+                lines[parent] ??= $"{parent}";
+                
+                // add vertex + weight to parent's string & visa versa
                 lines[parent] += $" {vertex.Id} {vertex.Key.ToString("F1")}";
                 lines[vertex.Id] += $" {parent} {vertex.Key.ToString("F1")}";
             });
-
+            // write the array of strings to file
             writer.WriteAllLines(lines);
         }
     }
-}
-// vertex.Edges.ForEach(e => line += $" {e.V} {e.Weight.ToString("F1")}");
-
-// var neighbors = graph.Vertices
-//     .Where(u => u.Parent == vertex.Id && vertex.Edges.Exists(e => e.V == u.Id));
-
-// var edges = vertex.Edges
-//     .Where(e => graph.Vertices.Find(v => v.Id == e.V).Parent == vertex.Id);
\ No newline at end of file
+}
\ No newline at end of file