changed the ownership of all instances of GraphEdge in a way that each instance of graphNode exlusively owns the outgoing graph edges and holds non-owning references to incoming GraphEdges

Author: gary-vladimir

src/chatlogic.cpp

@@ -35,11 +35,8 @@ ChatLogic::~ChatLogic()
     // delete chatbot instance
     delete _chatBot;
 
-    // delete all edges
-    for (auto it = std::begin(_edges); it != std::end(_edges); ++it)
-    {
-        delete *it;
-    }
+    // No need to manually delete edges now.
+    // The child nodes' unique_ptr<GraphEdge> will handle that.
 
     ////
     //// EOF STUDENT CODE
@@ -161,16 +158,16 @@ void ChatLogic::LoadAnswerGraphFromFile(std::string filename)
                             auto childNode = std::find_if(_nodes.begin(), _nodes.end(), [&childToken](std::unique_ptr<GraphNode> &node) { return node->GetID() == std::stoi(childToken->second); });
 
                             // create new edge
-                            GraphEdge *edge = new GraphEdge(id);
-                            _edges.push_back(edge);
+                            auto edge = std::make_unique<GraphEdge>(id);
+                            // _edges.push_back(edge);
                             edge->SetChildNode(childNode->get());
                             edge->SetParentNode(parentNode->get());
                             // find all keywords for current node
                             AddAllTokensToElement("KEYWORD", tokens, *edge);
 
                             // store reference in child node and parent node
-                            (*childNode)->AddEdgeToParentNode(edge);
-                            (*parentNode)->AddEdgeToChildNode(edge);
+                            (*childNode)->AddEdgeToParentNode(edge.get());
+                            (*parentNode)->AddEdgeToChildNode(std::move(edge));
                         }
 
                         ////

src/chatlogic.h

@@ -19,7 +19,7 @@ class ChatLogic
 
     // data handles (owned)
     std::vector<std::unique_ptr<GraphNode>> _nodes;
-    std::vector<GraphEdge *> _edges;
+    // std::vector<GraphEdge *> _edges;
 
     ////
     //// EOF STUDENT CODE

src/graphnode.cpp

@@ -11,6 +11,8 @@ GraphNode::~GraphNode()
     //// STUDENT CODE
     ////
 
+    // We do NOT delete _parentEdges here, since they are non‐owning!
+    // The unique_ptr in _childEdges will automatically free the GraphEdges.
 
     ////
     //// EOF STUDENT CODE
@@ -26,9 +28,9 @@ void GraphNode::AddEdgeToParentNode(GraphEdge *edge)
     _parentEdges.push_back(edge);
 }
 
-void GraphNode::AddEdgeToChildNode(GraphEdge *edge)
+void GraphNode::AddEdgeToChildNode(std::unique_ptr<GraphEdge> edge)
 {
-    _childEdges.push_back(edge);
+    _childEdges.push_back(std::move(edge));
 }
 
 //// STUDENT CODE
@@ -52,7 +54,7 @@ GraphEdge *GraphNode::GetChildEdgeAtIndex(int index)
     //// STUDENT CODE
     ////
 
-    return _childEdges[index];
+    return _childEdges[index].get();
 
     ////
     //// EOF STUDENT CODE

src/graphnode.h

@@ -4,7 +4,7 @@
 #include <vector>
 #include <string>
 #include "chatbot.h"
-
+#include <memory>
 
 // forward declarations
 class GraphEdge;
@@ -16,7 +16,7 @@ class GraphNode
     ////
 
     // data handles (owned)
-    std::vector<GraphEdge *> _childEdges;  // edges to subsequent nodes
+    std::vector<std::unique_ptr<GraphEdge>> _childEdges;  // edges to subsequent nodes
 
     // data handles (not owned)
     std::vector<GraphEdge *> _parentEdges; // edges to preceding nodes 
@@ -37,14 +37,14 @@ class GraphNode
     // getter / setter
     int GetID() { return _id; }
     int GetNumberOfChildEdges() { return _childEdges.size(); }
+    int GetNumberOfParents() { return _parentEdges.size(); }
     GraphEdge *GetChildEdgeAtIndex(int index);
     std::vector<std::string> GetAnswers() { return _answers; }
-    int GetNumberOfParents() { return _parentEdges.size(); }
 
     // proprietary functions
     void AddToken(std::string token); // add answers to list
     void AddEdgeToParentNode(GraphEdge *edge);
-    void AddEdgeToChildNode(GraphEdge *edge);
+    void AddEdgeToChildNode(std::unique_ptr<GraphEdge> edge);
 
     //// STUDENT CODE
     ////