change iterator structure to actually do an in order iterate

Map.hpp

@@ -1,6 +1,8 @@
 // commenting everything out when I commit so all commits my code technically
 // compiles
 #include <algorithm>
+#include <cstddef>
+#include <deque>
 #include <initializer_list>
 #include <iterator>
 #include <optional>
@@ -24,16 +26,28 @@ public:
   // TODO: Iterator functionality
   class Iterator {
   public:
-    using underlying = typename std::vector<std::optional<ValueType>>::iterator;
-
   private:
-    underlying store_iter;
+    // in order traversal, deque used as the stack we traverse up after each
+    // right hand side traversal completes
+    //
+    // if a right child exists traverse down to the left most child of that
+    // child pushing to stack elements that are passed if it doesn't pop from
+    // the stack
+    //
+    std::vector<ValueType> &parent;
+    std::deque<std::size_t> forward_traversal;
+    std::deque<std::size_t> backward_traversal;
+    std::size_t current;
 
   public:
     Iterator() = delete;
-    Iterator(underlying iter) : store_iter{iter} {}
+    Iterator(std::vector<ValueType> &parent, std::size_t current)
+        : parent{parent}, forward_traversal{}, backward_traversal{},
+          current{current} {}
     ConstIterator to_const() const { return ConstIterator(this); }
-    Iterator &operator++() { return *this; }
+    Iterator &operator++() {
+      // TODO: implement this
+    }
     Iterator operator++(int) {
       Iterator tmp = *this;
       ++(*this);