wrote first version of addToTree() and wrote new recursive function addToTreeRec()

bintree.c

@@ -18,23 +18,61 @@
     void            clearTree       (TreeNode *root);
     unsigned int    treeSize        (const TreeNode *root);
 
+    // selfdeclaredfunctions
+    TreeNode        *addToTreeRec   (TreeNode *currentNode, TreeNode *newNode, CompareFctType compareFct, int *isDuplicate);
+
 
 // Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
 // if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
+
+//      returned Value is new root?
 TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
 {
+    // create a node
+    TreeNode *newNode;
 
-if (root == NULL)
-{
-    //root setzen
-}
-else
-{
-    //vergleichen und dann je links und rechts weiter
-    //      mit neuer rekursiver funktion?
-    //          in dieser jeweils nachschauen ob duplikat
+
+    newNode         = calloc(1, sizeof(TreeNode));
+    newNode->data   = calloc(1, dataSize);
+    newNode->left   = NULL;
+    newNode->right  = NULL;
+    memcpy(newNode->data, data, dataSize);
+
+
+    return addToTreeRec(root, newNode, compareFct, isDuplicate);
 }
 
+
+TreeNode *addToTreeRec(TreeNode *currentNode, TreeNode *newNode, CompareFctType compareFct, int *isDuplicate)
+{
+    if (currentNode == NULL)
+    {
+        isDuplicate = 0;
+        return newNode;
+    }
+    else if (compareFct(newNode->data, currentNode->data) < 0)
+    {
+        currentNode->left   = addToTreeRec(currentNode->left, newNode, compareFct, isDuplicate);
+    }
+    else if (compareFct(newNode->data, currentNode->data) > 0)
+    {
+        currentNode->right  = addToTreeRec(currentNode->right, newNode, compareFct, isDuplicate);
+    }
+    else
+    {
+        //duplicate
+        if (isDuplicate == NULL)
+        {
+            return newNode;
+        }
+        else
+        {
+            isDuplicate = 1;
+        }
+    }
+
+
+    return currentNode;
 }