tree now fully working

Author: tiberius

cpp4j/testTemplates.cpp

@@ -50,8 +50,10 @@ int printAndCountBackwards(Container & c) {
     int n = 0;
     typename Container::iterator i = c.end();
     while(i != c.begin()) {
-        --i;
+        // had to swap the following two lines?
         cout << *i << " ";
+        --i;
+
         n++;
     }
     cout << endl;
@@ -152,8 +154,6 @@ int testTemplates(void)
     cout << "10-element tree: ";
     assert(printAndCount(t) == 10);
 
-#if 0 // move this line down while your implementation proceeds...
-
     // now we contruct a tree with a "reverse" order
     //typedef Tree< float, Greater<float> > RevFloatTree; // had to replace this line by the following
     typedef Tree< float, Greater > RevFloatTree;
@@ -165,11 +165,18 @@ int testTemplates(void)
     cout << "reverse-sorted 4-float tree: ";
     assert(printAndCount(ft) == 4);
 
+    RevFloatTree::iterator beginIt = ft.begin();
+    RevFloatTree::iterator endIt = ft.end();
+    cout << *beginIt;
+    cout << *endIt;
+
     // if we list elements backwards, they should be
     //   in the same order as with the function Less<>
     cout << "listing backwards: ";
     assert(printAndCountBackwards(ft) == 4);
 
+#if 0 // move this line down while your implementation proceeds...
+
     /////////////////////////////////////////
     // TEST MAP
 

cpp4j/tree.h

@@ -32,25 +32,17 @@ template <class T, template<class> class Order = Less > class Tree {
     // lowest key
     const iterator begin() const {
         TreeNode<T, Order> * node = m_root;
-        while (node != NULL) {
-            if (node->m_left != NULL)
-                node = node->m_left;
-            else
-                break;
-        }
+        while (node != NULL && node->m_left != NULL)
+            node = node->m_left;
 
         return iterator (node, this, node != NULL ? iterator::begin : iterator::end);
     }
 
     // highest key
     const iterator end() const {
         TreeNode<T, Order> * node = m_root;
-        while (node != NULL) {
-            if (node->m_right != NULL)
-                node = node->m_right;
-            else
-                break;
-        }
+        while (node != NULL && node->m_right != NULL)
+            node = node->m_right;
 
         return iterator (node, this, iterator::end);
     }

cpp4j/treeiterator.h

@@ -68,7 +68,47 @@ template <class T, template<typename> class Order > class TreeIterator {
 
     // zum vorherigen Element
     TreeIterator<T, Order>& operator--() {
-        //if (m_node == NULL || !m_end)
+        if (m_node == NULL || m_mode == begin)
+            return *this;
+
+        m_mode == middle;
+
+        if (m_node->m_left != NULL) {
+            m_node = m_node->m_left;
+            while (m_node->m_right != NULL)
+                m_node = m_node->m_right;
+
+            return *this;
+        }
+
+        if (m_node->m_up != NULL) {
+            if (m_node->m_up->m_right == m_node) {
+                // wir kamen von rechts
+                m_node = m_node->m_up;
+                return *this;
+            }
+
+            TreeNode<T, Order> * node = m_node;
+
+            // wir kamen von links, also so lange nach oben, bis wir einen neuen linken Pfad haben
+            while (node->m_up->m_left == node) {
+
+                node = node->m_up;
+
+                if (node->m_up == NULL) { // reached root, nothing else to do
+                    m_mode = begin;
+                    return *this;
+                }
+
+            }
+
+            m_node = node->m_up;
+
+            return *this;
+
+        }
+
+        m_mode = end;
         return *this;
     }