implemented method to return neighbours of node a, though not entirely working currently

YellowGraph.cs

@@ -24,9 +24,15 @@ class YellowGraph : Graph {
     }
     
     public void AddEdge(Node a, Node b, int c) {
-        adjMatrix[a.Id,b.Id] = c; //adds cost between two nodes in the adjacency matrix to imply of a corresponding edge between the two nodes
-            
-    }   
+        
+        if(a.Id >= adjMatrix.GetLength(0) || b.Id >= adjMatrix.GetLength(1))
+        {
+            Console.WriteLine("Matrix out of bounds"); //ensure we don't exceed the size of the matrix
+        } else if (c >= 0) { //Only add cost to adjMatrix if cost is postive
+            adjMatrix[a.Id,b.Id] = c; //adds cost between two nodes in the adjacency matrix to imply of a corresponding edge between the two nodes
+        }
+    }
+       
     
     public List<Node> Nodes() {
 		return nodes; //returns all the nodes
@@ -34,6 +40,12 @@ class YellowGraph : Graph {
 
 	public List<Node> Neighbours(Node a) {
 		List<Node> neighbours = new List<Node>(); //creates a list nodes
+        
+        for(int i = 0; i < adjMatrix.GetLength(1); i++){ //look for neighbours of node in the matrix
+            if(adjMatrix[a.Id, i] != 0) //if we find a cost that is not 0, it means there is an edge between the nodes
+                neighbours.Add(a.Id(i)); //get node and add it to the list
+        } 
+        
         return neighbours; //returns all the neighbours
 	}