diff --git a/bintree.c b/bintree.c
index 5cf82a9..82d2789 100644
--- a/bintree.c
+++ b/bintree.c
@@ -1,36 +1,106 @@
-#include <string.h>
-#include "stack.h"
 #include "bintree.h"
+#include "stack.h"
+#include <string.h>
 
-//TODO: binären Suchbaum implementieren
+// TODO: binären Suchbaum implementieren
 /*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
-    * `clearTree`: gibt den gesamten Baum frei (rekursiv),
-    * `treeSize`: zählt die Knoten im Baum (rekursiv),
-    * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */
+ * `clearTree`: gibt den gesamten Baum frei (rekursiv),
+ * `treeSize`: zählt die Knoten im Baum (rekursiv),
+ * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */
 
-// 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).
-TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
-{
+// typedef int (*CompareFctType)(const void *arg1, const void *arg2);
+//  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).
+TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize,
+                    CompareFctType compareFct, int *isDuplicate) {
 
+  if (isDuplicate) {
+    *isDuplicate = 0;
+  }
+
+  if (root == NULL) {
+    TreeNode *node = malloc(sizeof(TreeNode));
+    node->data = malloc(dataSize);
+    memcpy(node->data, data, dataSize);
+    node->left = NULL;
+    node->right = NULL;
+    return node;
+  }
+
+  int cmp = compareFct(data, root->data);
+
+  if (cmp < 0) {
+    root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
+  } else if (cmp > 0) {
+    root->right =
+        addToTree(root->right, data, dataSize, compareFct, isDuplicate);
+  } else {
+    // Duplikat
+    if (isDuplicate) {
+      *isDuplicate = 1;
+    }
+  }
+  return root;
 }
 
-// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
-// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
-// push the top node and push all its left nodes.
-void *nextTreeData(TreeNode *root)
-{
+// Iterates over the tree given by root. Follows the usage of strtok. If tree is
+// NULL, the next entry of the last tree given is returned in ordering
+// direction. Use your implementation of a stack to organize the iterator. Push
+// the root node and all left nodes first. On returning the next element, push
+// the top node and push all its left nodes.
+void *nextTreeData(TreeNode *root) {
 
+  static StackNode *stack = NULL;
+
+  // Neue Iteration starten
+  if (root != NULL) {
+    clearStack(&stack);
+
+    TreeNode *curr = root;
+
+    // Alle linken Kinder pushen
+    while (curr != NULL) {
+      stack = push(stack, curr);
+      curr = curr->left;
+    }
+  }
+
+  // Wenn leer → fertig
+  if (stack == NULL)
+    return NULL;
+
+  // Oberstes Element lesen
+  TreeNode *node = (TreeNode *)stack->data;
+  stack = pop(stack);
+
+  // Jetzt den rechten Teilbaum verarbeiten
+  TreeNode *curr = node->right;
+  while (curr != NULL) {
+    stack = push(stack, curr);
+    curr = curr->left;
+  }
+
+  return node->data;
 }
 
 // Releases all memory resources (including data copies).
-void clearTree(TreeNode *root)
-{
+void clearTree(TreeNode *root) {
 
+  if (root == NULL)
+    return;
+
+  clearTree(root->left);
+  clearTree(root->right);
+
+  free(root->data);
+  free(root);
 }
 
 // Returns the number of entries in the tree given by root.
-unsigned int treeSize(const TreeNode *root)
-{
+unsigned int treeSize(const TreeNode *root) {
 
+  if (root == NULL)
+    return 0;
+  return 1 + treeSize(root->left) + treeSize(root->right);
 }
\ No newline at end of file
diff --git a/highscores.txt b/highscores.txt
index ca5950d..cf3230a 100644
--- a/highscores.txt
+++ b/highscores.txt
@@ -1,2 +1,5 @@
 krisp;4986
+krisp;4985
+Kristin;4972
 player1;3999
+krisp;3991
diff --git a/makefile b/makefile
index c923a04..bc65fb7 100644
--- a/makefile
+++ b/makefile
@@ -36,16 +36,39 @@ $(program_obj_files): %.o: %.c
 # Unit Tests
 # --------------------------
 
-TEST_BIN = runTests
+STACK_TEST_BIN   = runStackTests
+NUMBERS_TEST_BIN = runNumbersTests
+BINARY_TEST_BIN  = runBinaryTests
 
-unitTests: stack.o test_stack.o
-	$(CC) $(FLAGS) -I$(unityfolder) -o $(TEST_BIN) stack.o test_stack.o $(unityfolder)/unity.c
+# --- Stack Tests ---
+stackTests: stack.o test_stack.o
+	$(CC) $(FLAGS) -I$(unityfolder) -o $(STACK_TEST_BIN) \
+	    stack.o test_stack.o $(unityfolder)/unity.c
 
 test_stack.o: test_stack.c
 	$(CC) $(FLAGS) -I$(unityfolder) -c test_stack.c -o test_stack.o
 
+
+# --- Numbers Tests ---
+numbersTests: numbers.o bintree.o stack.o test_numbers.o
+	$(CC) $(FLAGS) -I$(unityfolder) -o $(NUMBERS_TEST_BIN) \
+        numbers.o bintree.o stack.o test_numbers.o $(unityfolder)/unity.c
+
+test_numbers.o: test_numbers.c
+	$(CC) $(FLAGS) -I$(unityfolder) -c test_numbers.c -o test_numbers.o
+
+
+# --- Binary Tree Tests ---
+binaryTests: bintree.o stack.o test_binary.o
+	$(CC) $(FLAGS) -I$(unityfolder) -o $(BINARY_TEST_BIN) \
+	    bintree.o stack.o test_binary.o $(unityfolder)/unity.c
+
+test_binary.o: test_binary.c
+	$(CC) $(FLAGS) -I$(unityfolder) -c test_binary.c -o test_binary.o
+
+
 # --------------------------
 # Clean
 # --------------------------
 clean:
-	rm -f *.o doble
+	rm -f *.o doble $(STACK_TEST_BIN) $(NUMBERS_TEST_BIN) $(BINARY_TEST_BIN)
\ No newline at end of file
diff --git a/numbers.c b/numbers.c
index f59d9a2..414a4a4 100644
--- a/numbers.c
+++ b/numbers.c
@@ -1,26 +1,91 @@
-#include <stdlib.h>
-#include <stdio.h>
-#include <time.h>
-#include <string.h>
 #include "numbers.h"
 #include "bintree.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
 
-//TODO: getDuplicate und createNumbers implementieren
-/*  *   * Erzeugen eines Arrays mit der vom Nutzer eingegebenen Anzahl an Zufallszahlen.
-  * Sicherstellen, dass beim Befüllen keine Duplikate entstehen.
-  * Duplizieren eines zufälligen Eintrags im Array.
-  * in `getDuplicate()`: Sortieren des Arrays und Erkennen der doppelten Zahl durch Vergleich benachbarter Elemente. */
-
-// Returns len random numbers between 1 and 2x len in random order which are all different, except for two entries.
-// Returns NULL on errors. Use your implementation of the binary search tree to check for possible duplicates while
-// creating random numbers.
-unsigned int *createNumbers(unsigned int len)
-{
+int compareUnsignedInt(const void *a, const void *b) {
+  unsigned int x = *(unsigned int *)a;
+  unsigned int y = *(unsigned int *)b;
 
+  if (x < y)
+    return -1;
+  if (x > y)
+    return 1;
+  return 0;
 }
 
-// Returns only the only number in numbers which is present twice. Returns zero on errors.
-unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
-{
+// TODO: getDuplicate und createNumbers implementieren
+/**Erzeugen eines Arrays mit der vom Nutzer eingegebenen Anzahl an
+ * Zufallszahlen. Sicherstellen, dass beim Befüllen keine Duplikate entstehen.
+ * Duplizieren eines zufälligen Eintrags im Array.
+ * in `getDuplicate()`: Sortieren des Arrays und Erkennen der doppelten Zahl
+ * durch Vergleich benachbarter Elemente. */
 
-}
\ No newline at end of file
+// Returns len random numbers between 1 and 2x len in random order which are all
+// different, except for two entries. Returns NULL on errors. Use your
+// implementation of the binary search tree to check for possible duplicates
+// while creating random numbers.
+unsigned int *createNumbers(unsigned int len) {
+  if (len < 2)
+    return NULL;
+
+  unsigned int *arr = malloc(sizeof(unsigned int) * len);
+  if (!arr)
+    return NULL;
+
+  TreeNode *root = NULL;
+  srand((unsigned int)time(NULL));
+
+  for (unsigned int i = 0; i < len - 1; i++) {
+    unsigned int num;
+    int isDuplicate;
+
+    do {
+      num = (rand() % (2 * len)) + 1;
+      isDuplicate = 0;
+
+      root = addToTree(root, &num, sizeof(unsigned int), compareUnsignedInt,
+                       &isDuplicate);
+
+    } while (isDuplicate); // nur akzeptieren, wenn eindeutig
+
+    arr[i] = num;
+  }
+
+  // Jetzt gezielt EIN Duplikat erzeugen
+  unsigned int duplicateIndex = rand() % (len - 1);
+  arr[len - 1] = arr[duplicateIndex];
+
+  clearTree(root);
+  return arr;
+}
+
+// Returns only the only number in numbers which is present twice. Returns zero
+// on errors.
+unsigned int getDuplicate(const unsigned int numbers[], unsigned int len) {
+  if (!numbers || len < 2)
+    return 0;
+
+  unsigned int *copy = malloc(sizeof(unsigned int) * len);
+  if (!copy)
+    return 0;
+
+  memcpy(copy, numbers, sizeof(unsigned int) * len);
+
+  // Sortierung
+  qsort(copy, len, sizeof(unsigned int), compareUnsignedInt);
+
+  // Duplikat finden: zwei gleiche nebeneinander
+  unsigned int duplicate = 0;
+  for (unsigned int i = 0; i < len - 1; i++) {
+    if (copy[i] == copy[i + 1]) {
+      duplicate = copy[i];
+      break;
+    }
+  }
+
+  free(copy);
+  return duplicate;
+}
diff --git a/test_binary.c b/test_binary.c
new file mode 100644
index 0000000..a0d9cbc
--- /dev/null
+++ b/test_binary.c
@@ -0,0 +1,105 @@
+#include "unity.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "bintree.h"
+int compareUnsignedInt(const void *a, const void *b) {
+  unsigned int x = *(unsigned int *)a;
+  unsigned int y = *(unsigned int *)b;
+
+  if (x < y)
+    return -1;
+  if (x > y)
+    return 1;
+  return 0;
+}
+
+TreeNode *root = NULL;
+
+void setUp(void) {
+  root = NULL; // vor jedem Test leeren
+}
+
+void tearDown(void) { clearTree(root); }
+
+// Test, ob addToTree Knoten korrekt hinzufügt
+void test_addToTree_basic(void) {
+  int isDup;
+  unsigned int val = 10;
+  root = addToTree(root, &val, sizeof(val), compareUnsignedInt, &isDup);
+  TEST_ASSERT_NOT_NULL(root);
+  TEST_ASSERT_EQUAL_UINT(10, *(unsigned int *)root->data);
+  TEST_ASSERT_EQUAL_INT(0, isDup);
+  TEST_ASSERT_EQUAL_UINT(1, treeSize(root));
+}
+
+// Test, dass Duplikate erkannt werden
+void test_addToTree_duplicate(void) {
+  int isDup;
+  unsigned int val1 = 10, val2 = 10;
+  root = addToTree(root, &val1, sizeof(val1), compareUnsignedInt, &isDup);
+  TEST_ASSERT_EQUAL_INT(0, isDup);
+  root = addToTree(root, &val2, sizeof(val2), compareUnsignedInt, &isDup);
+  TEST_ASSERT_EQUAL_INT(1, isDup);
+  TEST_ASSERT_EQUAL_UINT(1, treeSize(root)); // Duplikate nicht hinzufügen
+}
+
+// Test nextTreeData Traversierung
+void test_nextTreeData_in_order(void) {
+  unsigned int values[] = {20, 10, 30};
+  int isDup;
+  for (int i = 0; i < 3; i++) {
+    root = addToTree(root, &values[i], sizeof(values[i]), compareUnsignedInt,
+                     &isDup);
+  }
+
+  unsigned int expected[] = {10, 20, 30};
+  int idx = 0;
+  void *data;
+
+  // **Neue Iteration starten**
+  data = nextTreeData(root);
+  while (data != NULL) {
+    TEST_ASSERT_EQUAL_UINT(expected[idx], *(unsigned int *)data);
+    idx++;
+    data = nextTreeData(NULL); // weitere Elemente abrufen
+  }
+
+  TEST_ASSERT_EQUAL_INT(3, idx); // alle 3 Knoten besucht
+}
+
+// Test clearTree gibt Speicher frei
+void test_clearTree(void) {
+  unsigned int val = 42;
+  int isDup;
+  root = addToTree(root, &val, sizeof(val), compareUnsignedInt, &isDup);
+  clearTree(root);
+  root = NULL; // clearTree löscht nicht die root-Variable selbst
+  TEST_ASSERT_NULL(root);
+}
+
+// Test treeSize zählt korrekt
+void test_treeSize(void) {
+  unsigned int vals[] = {10, 20, 5};
+  int isDup;
+  for (int i = 0; i < 3; i++) {
+    root =
+        addToTree(root, &vals[i], sizeof(vals[i]), compareUnsignedInt, &isDup);
+  }
+  TEST_ASSERT_EQUAL_UINT(3, treeSize(root));
+}
+
+int main(void) {
+  UNITY_BEGIN();
+
+  printf(
+      "\n------------------------binarytree test------------------------\n\n");
+
+  RUN_TEST(test_addToTree_basic);
+  RUN_TEST(test_addToTree_duplicate);
+  RUN_TEST(test_nextTreeData_in_order);
+  RUN_TEST(test_clearTree);
+  RUN_TEST(test_treeSize);
+  return UNITY_END();
+}
\ No newline at end of file
diff --git a/test_numbers.c b/test_numbers.c
new file mode 100644
index 0000000..8992bb8
--- /dev/null
+++ b/test_numbers.c
@@ -0,0 +1,61 @@
+#include "unity.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "numbers.h"
+
+#define TEST_ARRAY_LEN 100
+
+void test_createNumbers_length(void) {
+  unsigned int *arr = createNumbers(TEST_ARRAY_LEN);
+  TEST_ASSERT_NOT_NULL(arr);
+  free(arr);
+}
+
+void test_createNumbers_single_duplicate(void) {
+  unsigned int *arr = createNumbers(TEST_ARRAY_LEN);
+  TEST_ASSERT_NOT_NULL(arr);
+
+  unsigned int duplicate = getDuplicate(arr, TEST_ARRAY_LEN);
+  TEST_ASSERT_TRUE(duplicate > 0);
+
+  unsigned int count = 0;
+  for (unsigned int i = 0; i < TEST_ARRAY_LEN; i++) {
+    if (arr[i] == duplicate) {
+      count++;
+    }
+  }
+  TEST_ASSERT_EQUAL_UINT(2, count);
+
+  free(arr);
+}
+
+void test_getDuplicate_manual_array(void) {
+  unsigned int numbers[5] = {10, 20, 30, 40, 20};
+  unsigned int dup = getDuplicate(numbers, 5);
+  TEST_ASSERT_EQUAL_UINT(20, dup);
+}
+
+void test_getDuplicate_invalid_input(void) {
+  TEST_ASSERT_EQUAL_UINT(0, getDuplicate(NULL, 5));
+  unsigned int arr[1] = {42};
+  TEST_ASSERT_EQUAL_UINT(0, getDuplicate(arr, 1));
+}
+
+void setUp(void) {}
+void tearDown(void) {}
+
+int main(void) {
+
+  UNITY_BEGIN();
+
+  printf("\n------------------------numbers test------------------------\n\n");
+
+  RUN_TEST(test_createNumbers_length);
+  RUN_TEST(test_createNumbers_single_duplicate);
+  RUN_TEST(test_getDuplicate_manual_array);
+  RUN_TEST(test_getDuplicate_invalid_input);
+
+  return UNITY_END();
+}
diff --git a/test_stack.c b/test_stack.c
index 9f14a45..533af6a 100644
--- a/test_stack.c
+++ b/test_stack.c
@@ -41,13 +41,13 @@ void test_deleteTopElement(void) {
     stack = push(stack, &testInts[i]);
   }
 
-  TEST_ASSERT_EQUAL_PTR(&testInts[2], top(stack));
+  TEST_ASSERT_EQUAL_PTR(&testInts[2], stack->data);
 
   stack = pop(stack);
-  TEST_ASSERT_EQUAL_PTR(&testInts[1], top(stack));
+  TEST_ASSERT_EQUAL_PTR(&testInts[1], stack->data);
 
   stack = pop(stack);
-  TEST_ASSERT_EQUAL_PTR(&testInts[0], top(stack));
+  TEST_ASSERT_EQUAL_PTR(&testInts[0], stack->data);
 
   stack = pop(stack);
   TEST_ASSERT_NULL(stack);
@@ -98,7 +98,7 @@ int main(void) {
 
   UNITY_BEGIN();
 
-  printf("------------------------stack test------------------------\n");
+  printf("\n------------------------stack test------------------------\n\n");
 
   RUN_TEST(test_createNode);
   RUN_TEST(test_pushDataToStack);