Fixed first vertex bug, use pointers to track vertices (in case we want to move them easily later), and added a formula for vertex distance calculations

graph.h

@@ -11,37 +11,41 @@
 
 using std::list;
 
-struct Vertex
+class Vertex
 {
+  public:
     int x;
     int y;
     int x_min;
     int x_max;
     int y_min;
     int y_max;
+
+    static float distance(Vertex a, Vertex b);
 };
 
 struct Edge
 {
-    Vertex a;
-    Vertex b;
+    Vertex* a;
+    Vertex* b;
 };
 
 class Graph
 {
  public:
-    Graph() {}
+    Graph();
+    ~Graph();
 
     bool vertex_present(int x, int y, int size);
 
-    list<Vertex> get_vertices() { return vertices; }
+    list<Vertex*> get_vertices() { return vertices; }
     list<Edge> get_edges() { return edges; }
 
     void add_vertex(int x, int y, int size);
 
  private:
-    Vertex last_vertex;
-    list<Vertex> vertices;
+    Vertex* last_vertex;
+    list<Vertex*> vertices;
     list<Edge> edges;
 };