Add Graph::new()

src/main.rs

@@ -6,12 +6,7 @@ use models::Vertex;
 
 fn main() {
     // TODO: Move this graph example into one or more tests.
-    let mut graph = Graph {
+    let mut graph = Graph::new();
-        // TODO: The initializations should happen in an initializer or constructor
-        incidence_headers: vec![],
-        next_incidences: vec![],
-        incidence_vertices: vec![],
-    };
     let vertices: [Vertex; 10] = core::array::from_fn(|_| graph.add_vertex());
     graph.add_edge(vertices[0], vertices[1]);
     graph.add_edge(vertices[1], vertices[2]);

src/models.rs

@@ -26,6 +26,14 @@ pub struct Graph {
 // TODO: Add iterator of edges.
 // TODO: Add iterator of vertex neighbors, see 'fn add_adjacent()'.
 impl Graph {
+    pub fn new() -> Graph {
+        Graph {
+            incidence_headers: vec![],
+            next_incidences: vec![],
+            incidence_vertices: vec![],
+        }
+    }
+
     pub fn vertex_count(&self) -> usize {
         self.incidence_headers.len()
     }