diff --git a/bintree.c b/bintree.c
index 754b60c..54f423e 100644
--- a/bintree.c
+++ b/bintree.c
@@ -2,6 +2,7 @@
 #include "stack.h"
 #include "bintree.h"
 
+static StackNode *stack;
 // TODO: binären Suchbaum implementieren
 /*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
  * `clearTree`: gibt den gesamten Baum frei (rekursiv),
@@ -12,25 +13,23 @@
 // if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
 TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
 {
-    TreeNode newNode = {data, NULL, NULL};
-    
-
-    if(root == NULL)
+    if (root == NULL)
     {
-        return &newNode;
+        TreeNode *newNode = malloc(sizeof(TreeNode));
+        newNode->data = malloc(dataSize);
+        newNode->data = data;
+        newNode->left = NULL;
+        newNode->right = NULL;
+        return newNode;
     }
-
-    if (data < root->data)
+    if (compareFct(root->data, data) < 0)
     {
-        root->left = addToTree(root->left, data, dataSize,compareFct, isDuplicate);
+        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
     }
-    else if(data > root->data)
+    else if (compareFct(root->data, data) > 0)
     {
-       root->right = addToTree(root->right, data, dataSize,compareFct, isDuplicate);
+        root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
     }
-
-
-
     return root;
 }
 
@@ -39,9 +38,11 @@ TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFc
 // push the top node and push all its left nodes.
 void *nextTreeData(TreeNode *root)
 {
+    return NULL;
 
 }
 
+
 // Releases all memory resources (including data copies).
 void clearTree(TreeNode *root)
 {
@@ -49,7 +50,7 @@ void clearTree(TreeNode *root)
     {
         return;
     }
-    
+
     if (root->left != NULL)
     {
         clearTree(root->left);
diff --git a/numbers.c b/numbers.c
index 9b5817a..5a354c6 100644
--- a/numbers.c
+++ b/numbers.c
@@ -34,7 +34,8 @@ unsigned int *createNumbers(unsigned int len)
 {
   srand(time(NULL));
   unsigned int *array = (unsigned int *)malloc(len * sizeof(unsigned int));
-  int randomNr, randomPos, counter;
+  int randomNr, randomPos, counter, filler;
+  
 
   if (array == NULL)
   {
@@ -45,45 +46,25 @@ unsigned int *createNumbers(unsigned int len)
   {
     array[i] = 0;
   }
-
-  randomNr = rand() % (2 * len + 1);
-  randomPos = rand() % (len);
-  array[randomPos] = randomNr;
-  do
+  
+  for (int i = 0; i < len; i++)
   {
-    randomPos = rand() % (len);
-  } while (array[randomPos] != 0);
-  array[randomPos] = randomNr;
-
-  while (!checkArray(array, len, 0))
-  {
-    counter = 0;
     do
     {
-      if (counter == len)
-      {
-        return NULL;
-      }
-
-      randomPos = rand() % (len);
-      counter++;
-    } while (array[randomPos] != 0);
-
-    counter = 0;
-    do
-    {
-      if (counter == len * 2)
-      {
-        return NULL;
-      }
-
-      randomNr = rand() % (2 * len + 1);
-      counter++;
-    } while (!checkArray(array, len, randomNr));
-
-    array[randomPos] = randomNr;
+      array[i] = rand() % (2 * len) + 1;
+    } while (!checkArray(array, i, array[i]));
   }
 
+  randomPos = rand() % len;
+  randomNr = array[randomPos];
+
+  filler = randomPos;
+  while(filler == randomPos)
+  {
+    filler = rand() % len;
+  }
+  array[filler] = randomNr;
+  
   return array;
 }
 
diff --git a/stack.c b/stack.c
index 2315722..5a10712 100644
--- a/stack.c
+++ b/stack.c
@@ -13,7 +13,7 @@ StackNode *push(StackNode *stack, void *data)
     StackNode *tempNode, *newNode;
 
     newNode = malloc(sizeof(StackNode));
-    newNode->value = *(int *)data;
+    newNode->value = data;
     newNode->next = NULL;
 
     if (stack == NULL)
diff --git a/stack.h b/stack.h
index d7cc86a..0d1130c 100644
--- a/stack.h
+++ b/stack.h
@@ -9,7 +9,7 @@ The latest element is taken from the stack. */
 
 //TODO: passenden Datentyp als struct anlegen
 typedef struct Node {
-    int value;
+    void *value;
     struct Node* next;
 } StackNode;
 
diff --git a/test_stack.c b/test_stack.c
index 2e59a8f..7e70b58 100644
--- a/test_stack.c
+++ b/test_stack.c
@@ -25,7 +25,7 @@ void test_push(void)
     TEST_ASSERT_EQUAL_INT(2, testNode->next->value);
 }
 
-StackNode* setup(int value, StackNode* next) {
+StackNode* setup(void *value, StackNode* next) {
     StackNode* node = malloc(sizeof(StackNode)); // allocate memory on heap
     if (node == NULL) {
         perror("malloc failed");