Added further functionality to check for connected nodes and disconnect

9fans.net/go

@@ -1 +0,0 @@
-Subproject commit 65b8cf069318223b1e722b4b36e729e5e9bb9eab

graphTester.go

@@ -6,15 +6,18 @@ import (
 )
 
 func main() {
-	n := &graph.Node{Value: "1"}
-	n2 := &graph.Node{Value: "2"}
-	n3 := &graph.Node{Value: "3"}
+	n := new(graph.Node)
+	n.Value = "1"
+	n2 := new(graph.Node)
+	n2.Value = "2"
+	n3 := new(graph.Node)
+	n3.Value = "3"
 
 	n.Connect(n2)
 	n.Connect(n3)
-	n3.Connect(n.GetConnections()[0])
-	//n.Disconnect(&n2) test
-	//fmt.Println(n.RemovePointerTo(n3))
+	n2.Connect(n3)
+	n.DisconnectAll()
+	fmt.Println(n.IsConnectedTo(n3))
 	fmt.Println("n -> n2: ", n2.IsConnectedTo(n), " n <- n2: ", n.IsConnectedTo(n2))
 	fmt.Println("n -> n3: ", n.IsConnectedTo(n3), " n <- n3: ", n3.IsConnectedTo(n))
 	fmt.Println("n2 -> n3: ", n2.IsConnectedTo(n3), " n2 <- n3: ", n3.IsConnectedTo(n2))

lib/collection/stack.go

@@ -1,27 +0,0 @@
-// Package collection implements a generic stack.
-package collection
-
-// The zero value for Stack is an empty stack ready to use.
-type Stack struct {
-    data []interface{}
-}
-
-// Push adds x to the top of the stack.
-func (s *Stack) Push(x interface{}) {
-    s.data = append(s.data, x)
-}
-
-// Pop removes and returns the top element of the stack.
-// It’s a run-time error to call Pop on an empty stack.
-func (s *Stack) Pop() interface{} {
-    i := len(s.data) - 1
-    res := s.data[i]
-    s.data[i] = nil  // to avoid memory leak
-    s.data = s.data[:i]
-    return res
-}
-
-// Size returns the number of elements in the stack.
-func (s *Stack) Size() int {
-    return len(s.data)
-}

lib/graph/hello.go

@@ -11,6 +11,14 @@ type Node struct {
 	messages    []string
 }
 
+//GetConnection returns the i'th connected node if it exists
+func (n *Node) GetConnection(i int) (*Node, error) {
+	if n.NrOfConnectedNodes() > i {
+		return n.connections[i], nil
+	}
+	return n, fmt.Errorf("slice out of bounds")
+}
+
 //GetConnections returns all connections
 func (n *Node) GetConnections() []*Node {
 	return n.connections
@@ -29,7 +37,9 @@ func (n *Node) Connect(otherNode *Node) {
 
 //SetPointTo sets this Node to point towards the given Node
 func (n *Node) SetPointTo(otherNode *Node) {
+	if n.IsConnectedTo(otherNode) == false {
 		n.connections = append(n.connections, otherNode)
+	}
 }
 
 //RemovePointerTo removes pointer to a node (a "child")
@@ -56,20 +66,28 @@ func (n *Node) Disconnect(otherNode *Node) int {
 	return -1
 }
 
+//DisconnectAll disconnects all Nodes
+func (n *Node) DisconnectAll() {
+	for _, v := range n.connections {
+		n.Disconnect(v)
+	}
+}
+
 //IsConnectedTo checks if this node is connected (has a pointer) to the given node
 func (n *Node) IsConnectedTo(otherNode *Node) bool {
-	if n.GetIndexOf(otherNode) != -1 {
+	nPointsToOther := n.GetIndexOf(otherNode)
+	otherPointsToN := otherNode.GetIndexOf(n)
+	if nPointsToOther != -1 && otherPointsToN != -1 {
 		return true
 	}
 	return false
 }
 
-//GetIndexOf gets the index of the specified node
+//GetIndexOf gets the index of the specified node.
+//May alternatively be used to check if n is pointing to otherNode
 func (n *Node) GetIndexOf(otherNode *Node) int {
-	for i := range n.connections {
-		//fmt.Printf("%p and %p \n", n.connections[i], otherNode)
-
-		if n.connections[i] == otherNode { //addresses are compared
+	for i, v := range n.connections {
+		if v == otherNode { //addresses are compared
 			return i
 		}
 	}