Fixed, CXXGraph::Node::getData() should not be const #438 (#462)

* Fixed, CXXGraph::Node::getData() should not be const #438

* Fixed the build failure

* Fix some lint issues

* Update Node_decl.h

Fixed lint issue

* Update Node_impl.hpp

fixed lint issue

Author: yapa-ymtl

include/CXXGraph/Node/Node_decl.h

@@ -48,6 +48,7 @@ class Node {
   const CXXGraph::id_t &getId() const;
   const std::string &getUserId() const;
   const T &getData() const;
+  T& getData();
   void setData(T &&new_data);
   // operator
   bool operator==(const Node<T> &b) const;

include/CXXGraph/Node/Node_impl.hpp

@@ -65,6 +65,11 @@ const T &Node<T>::getData() const {
   return data;
 }
 
+template <typename T>
+T &Node<T>::getData() {
+  return data;
+}
+
 template <typename T>
 void Node<T>::setData(T &&new_data) {
   this->data = std::move(new_data);
@@ -92,4 +97,4 @@ std::ostream &operator<<(std::ostream &os, const Node<T> &node) {
 
 }  // namespace CXXGraph
 
-#endif  // __CXXGRAPH_NODE_IMPL_H__
+#endif  // __CXXGRAPH_NODE_IMPL_H__