diff --git a/bintree.c b/bintree.c
index 5cf82a9..9761ea8 100644
--- a/bintree.c
+++ b/bintree.c
@@ -1,36 +1,128 @@
 #include <string.h>
 #include "stack.h"
 #include "bintree.h"
+#include <stdlib.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)
 {
+    if (isDuplicate)
+        *isDuplicate = 0;
 
+    if (root == NULL)
+    {
+        TreeNode *newNode = (TreeNode *)malloc(sizeof(TreeNode));
+        if (!newNode)
+        {
+            return NULL;
+        }
+        newNode->data = malloc(dataSize);
+        if (!newNode->data)
+        {
+            free(newNode);
+            return NULL;
+        }
+
+        memcpy(newNode->data, data, dataSize);
+        newNode->left = NULL;
+        newNode->right = NULL;
+        return newNode;
+    }
+
+    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
+    {
+
+        if (isDuplicate)
+        {
+            *isDuplicate = 1; // ignorieren
+            return root;
+        }
+        else
+        {
+            // Duplikate erlaubt -> nach rechts
+            root->right = addToTree(root->right, data, dataSize, compareFct, NULL);
+        }
+    }
+    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.
+static StackNode *iterator = NULL;
 void *nextTreeData(TreeNode *root)
 {
+      if (root != NULL)
+    {
+        clearStack(iterator);
+        iterator = NULL;
 
+        // Root + alle linken Nachfolger pushen
+        TreeNode *current = root;
+        while (current != NULL)
+        {
+            iterator = push(iterator, current);
+            current = current->left;
+        }
+    }
+
+    // Wenn Stack leer -> fertig
+    if (iterator == NULL)
+    {   
+        return NULL;
+    }
+     
+
+    // Top-Node holen
+    TreeNode *node = (TreeNode *)top(iterator);
+    iterator = pop(iterator);
+
+    // rechten Teilbaum + linke Kette pushen
+    TreeNode *right = node->right;
+    while (right != NULL)
+    {
+        iterator = push(iterator, right);
+        right = right->left;
+    }
+
+    return node->data;
 }
 
 // Releases all memory resources (including data copies).
 void clearTree(TreeNode *root)
 {
+    if (root != NULL)
+    {
+        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)
 {
+    if (root == NULL)
+        return 0;
 
+    return 1 + treeSize(root->left) + treeSize(root->right);
 }
\ No newline at end of file
diff --git a/bintree.o b/bintree.o
new file mode 100644
index 0000000..861d2b2
Binary files /dev/null and b/bintree.o differ
diff --git a/doble.exe b/doble.exe
new file mode 100644
index 0000000..85ea193
Binary files /dev/null and b/doble.exe differ
diff --git a/doble_initial.exe b/doble_initial.exe
new file mode 100644
index 0000000..3db2f66
Binary files /dev/null and b/doble_initial.exe differ
diff --git a/highscore.o b/highscore.o
new file mode 100644
index 0000000..e9b31f1
Binary files /dev/null and b/highscore.o differ
diff --git a/highscores.txt b/highscores.txt
index 4edd5a7..6977b89 100644
--- a/highscores.txt
+++ b/highscores.txt
@@ -1 +1,2 @@
-player1;3999
+player_name;5967
+jan;2993
diff --git a/main.o b/main.o
new file mode 100644
index 0000000..a5219de
Binary files /dev/null and b/main.o differ
diff --git a/makefile b/makefile
index 1f15f75..b03448f 100644
--- a/makefile
+++ b/makefile
@@ -35,15 +35,41 @@ $(program_obj_filesobj_files): %.o: %.c
 # --------------------------
 # Unit Tests
 # --------------------------
-unitTests:
-	echo "needs to be implemented"
+unitTests: test_stack test_tree test_numbers
+test_stack: test_stack.o stack.o unity/unity.c
+	$(CC) $(FLAGS) -I$(unityfolder) $^ -o test_stack
+
+test_tree: test_tree.o bintree.o stack.o unity/unity.c
+	$(CC) $(FLAGS) -I$(unityfolder) $^ -o test_tree
+
+test_numbers: test_numbers.o numbers.o bintree.o stack.o unity/unity.c
+	$(CC) $(FLAGS) -I$(unityfolder) $^ -o test_numbers
+
+test_stack.o: test_stack.c
+	$(CC) -c $(FLAGS) -I$(unityfolder) $< -o $@
+
+stack.o: stack.c
+	$(CC) -c $(FLAGS) $< -o $@
+
+test_tree.o: test_tree.c
+	$(CC) -c $(FLAGS) -I$(unityfolder) $< -o $@
+
+test_numbers.o: test_numbers.c
+	$(CC) -c $(FLAGS) -I$(unityfolder) $< -o $@
+
+bintree.o: bintree.c
+	$(CC) -c $(FLAGS) $< -o $@
+
+numbers.o: numbers.c
+	$(CC) -c $(FLAGS) $< -o $@
+
 
 # --------------------------
 # Clean
 # --------------------------
 clean:
 ifeq ($(OS),Windows_NT)
-	del /f *.o doble
+	del /f *.o doble $(TEST_BIN).exe
 else
-	rm -f *.o doble
+	rm -f *.o doble $(TEST_BIN)
 endif
\ No newline at end of file
diff --git a/numbers.c b/numbers.c
index f59d9a2..24b4ae3 100644
--- a/numbers.c
+++ b/numbers.c
@@ -5,22 +5,108 @@
 #include "numbers.h"
 #include "bintree.h"
 
-//TODO: getDuplicate und createNumbers implementieren
+// 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. */
+ * 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.
+
+static void duplicateRandomEntry(unsigned int *numbers, unsigned int len)
+{
+    if (!numbers || len < 2)
+        return;
+
+    unsigned int src = rand() % len;
+    unsigned int dst = rand() % len;
+
+    while (dst == src)
+        dst = rand() % len;
+
+    numbers[dst] = numbers[src];
+}
+
+
+static int compare(const void *a, const void *b)
+{
+    unsigned int x = *(const unsigned int *)a;
+    unsigned int y = *(const unsigned int *)b;
+    return (x > y) - (x < y);
+}
+
+
+
+
 unsigned int *createNumbers(unsigned int len)
 {
+ if (len < 2)
+        return NULL;
+
+    unsigned int *numbers = malloc(sizeof(unsigned int) * len);
+    if (!numbers)
+        return NULL;
+
+    static int seeded = 0;
+    if (!seeded) {
+        srand((unsigned)time(NULL));
+        seeded = 1;
+    }
+
+    TreeNode *root = NULL;
+    unsigned int i = 0;
+
+    while (i < len)
+    {
+        unsigned int val = (rand() % (2 * len)) + 1;
+        int isDup = 0;
+
+        root = addToTree(root, &val, sizeof(unsigned int), compare, &isDup);
+        if (!root) 
+        {          
+            free(numbers);  // malloc-Fehler
+            return NULL;
+        }
+
+        if (!isDup)
+            numbers[i++] = val;
+    }
+
+    duplicateRandomEntry(numbers, len);
+    clearTree(root);
+    return numbers;
 
 }
 
 // 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;
+  }
 
-}
\ No newline at end of file
+  unsigned int *copy = (unsigned int *)malloc(len * sizeof(unsigned int));
+  if (!copy)
+  {
+    return 0;
+  }
+
+  memcpy(copy, numbers, len * sizeof(unsigned int));
+  qsort(copy, len, sizeof(unsigned int), compare);
+
+  unsigned int dup = 0;
+  for (unsigned int i = 1; i < len; i++)
+  {
+    if (copy[i] == copy[i - 1])
+    {
+      dup = copy[i];
+      break;
+    }
+  }
+
+  free(copy);
+  return dup;
+}
diff --git a/numbers.o b/numbers.o
new file mode 100644
index 0000000..247f8c4
Binary files /dev/null and b/numbers.o differ
diff --git a/stack.c b/stack.c
index e3a90d4..a85e3d8 100644
--- a/stack.c
+++ b/stack.c
@@ -10,24 +10,53 @@
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data)
 {
+    StackNode *newNode = malloc(sizeof(StackNode));
+    if(newNode == NULL)
+    {
+        return stack;           //Speicher konnte nicht allokiert werden.
+    }
 
+    newNode->data = data;
+    newNode->next = stack;
+
+    return newNode;
 }
 
 // Deletes the top element of the stack (latest added element) and releases its memory. (Pointer to data has to be
 // freed by caller.)
 StackNode *pop(StackNode *stack)
 {
+    if (stack == NULL)
+    {
+        return NULL;            // stack leer nichts zu löschen
+    }
 
+    StackNode *next = stack->next;
+
+    free(stack);
+    return next;
 }
 
 // Returns the data of the top element.
 void *top(StackNode *stack)
 {
+    if(stack == NULL)
+    {
+        return NULL;
+    }
 
+    return stack->data;
 }
 
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
+    while (stack != NULL)
+    {
+       StackNode *next = stack->next;
+       free(stack);
 
+       stack = next;
+    }
+    
 }
\ No newline at end of file
diff --git a/stack.h b/stack.h
index f7d542d..98505af 100644
--- a/stack.h
+++ b/stack.h
@@ -9,6 +9,11 @@ The latest element is taken from the stack. */
 
 //TODO: passenden Datentyp als struct anlegen
 
+typedef struct StackNode {
+    void *data;
+    struct StackNode* next;
+} StackNode;
+
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);
 
diff --git a/stack.o b/stack.o
new file mode 100644
index 0000000..381a8d2
Binary files /dev/null and b/stack.o differ
diff --git a/test_numbers.c b/test_numbers.c
new file mode 100644
index 0000000..1db8867
--- /dev/null
+++ b/test_numbers.c
@@ -0,0 +1,72 @@
+#include <stdlib.h>
+#include "numbers.h"
+#include "unity.h"
+#include "unity_internals.h"
+
+void test_createNumbers_no_null(void) 
+{
+    unsigned int *arr = createNumbers(10);
+    TEST_ASSERT_NOT_NULL(arr);
+    free(arr);
+}
+
+void test_createNumbers_has_exactly_one_duplicate(void) 
+{
+    unsigned int len = 100;
+    unsigned int *arr = createNumbers(len);
+    TEST_ASSERT_NOT_NULL(arr);
+
+    unsigned int dup = getDuplicate(arr, len);
+    TEST_ASSERT_NOT_EQUAL(0, dup);
+
+    int count = 0;
+    for (unsigned int i = 0; i < len; i++) 
+    {
+        if (arr[i] == dup) 
+            count++;
+    }
+    
+    TEST_ASSERT_EQUAL(2, count);
+
+    free(arr);
+}
+
+void test_createNumbers_has_correct_value_range(void)
+{
+    unsigned int len = 10;
+    unsigned int *arr = createNumbers(len);
+    TEST_ASSERT_NOT_NULL(arr);
+
+    // Check all numbers are within valid range (1 to 2*len)
+    for (unsigned int i = 0; i < len; i++)
+    {
+        TEST_ASSERT_TRUE(arr[i] >= 1);
+        TEST_ASSERT_TRUE(arr[i] <= 2 * len);
+    }
+
+    free(arr);
+}
+
+void test_getDuplicate_returns_correct_value(void) 
+{
+    unsigned int arr[6] = {4, 1, 7, 7, 3, 2};
+    unsigned int d = getDuplicate(arr, 6);
+    TEST_ASSERT_EQUAL_UINT(7, d);
+}
+
+void setUp(void) { }
+void tearDown(void) { }
+
+int main(void) 
+{
+    UNITY_BEGIN();
+
+    printf("\n============================\n Numbers tests\n============================\n");
+
+    RUN_TEST(test_createNumbers_no_null);
+    RUN_TEST(test_createNumbers_has_exactly_one_duplicate);
+    RUN_TEST(test_createNumbers_has_correct_value_range);
+    RUN_TEST(test_getDuplicate_returns_correct_value);
+
+    return UNITY_END();
+}
\ No newline at end of file
diff --git a/test_numbers.exe b/test_numbers.exe
new file mode 100644
index 0000000..b176541
Binary files /dev/null and b/test_numbers.exe differ
diff --git a/test_stack.c b/test_stack.c
new file mode 100644
index 0000000..2bb7df6
--- /dev/null
+++ b/test_stack.c
@@ -0,0 +1,155 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "unity.h"
+#include "stack.h"
+
+// Hilfsfunktion: int dynamisch anlegen
+static int *makeInt(int value)
+{
+    int *p = (int *)malloc(sizeof(int));
+    if (p != NULL)
+    {
+        *p = value;
+    }
+    return p;
+}
+
+void test_pushAndTopReturnLastPushed(void)
+{
+    StackNode *stack = NULL;
+
+    int *v1 = makeInt(10);
+    int *v2 = makeInt(20);
+    int *v3 = makeInt(30);
+
+    TEST_ASSERT_NOT_NULL(v1);
+    TEST_ASSERT_NOT_NULL(v2);
+    TEST_ASSERT_NOT_NULL(v3);
+
+    stack = push(stack, v1);
+    TEST_ASSERT_NOT_NULL(stack);
+    TEST_ASSERT_EQUAL_PTR(v1, top(stack));
+    TEST_ASSERT_EQUAL_INT(10, *(int *)top(stack));
+
+    stack = push(stack, v2);
+    TEST_ASSERT_EQUAL_PTR(v2, top(stack));
+    TEST_ASSERT_EQUAL_INT(20, *(int *)top(stack));
+
+    stack = push(stack, v3);
+    TEST_ASSERT_EQUAL_PTR(v3, top(stack));
+    TEST_ASSERT_EQUAL_INT(30, *(int *)top(stack));
+
+    TEST_ASSERT_EQUAL_PTR(v3, top(stack));
+    free(v3);
+    stack = pop(stack);
+
+    TEST_ASSERT_EQUAL_PTR(v2, top(stack));
+    free(v2);
+    stack = pop(stack);
+
+    TEST_ASSERT_EQUAL_PTR(v1, top(stack));
+    free(v1);
+    stack = pop(stack);
+
+    TEST_ASSERT_NULL(stack);
+}
+
+void test_popOnEmptyStackReturnsNull(void)
+{
+    StackNode *stack = NULL;
+
+    StackNode *newStack = pop(stack);
+    TEST_ASSERT_NULL(newStack);
+
+    TEST_ASSERT_NULL(top(newStack));
+}
+
+void test_pushAndPopLifoOrder(void)
+{
+    StackNode *stack = NULL;
+
+    int *v1 = makeInt(1);
+    int *v2 = makeInt(2);
+    int *v3 = makeInt(3);
+
+    TEST_ASSERT_NOT_NULL(v1);
+    TEST_ASSERT_NOT_NULL(v2);
+    TEST_ASSERT_NOT_NULL(v3);
+
+    stack = push(stack, v1);
+    stack = push(stack, v2);
+    stack = push(stack, v3);
+
+    TEST_ASSERT_EQUAL_PTR(v3, top(stack));
+    TEST_ASSERT_EQUAL_INT(3, *(int *)top(stack));
+    free(v3);
+    stack = pop(stack);
+
+    TEST_ASSERT_EQUAL_PTR(v2, top(stack));
+    TEST_ASSERT_EQUAL_INT(2, *(int *)top(stack));
+    free(v2);
+    stack = pop(stack);
+
+
+    TEST_ASSERT_EQUAL_PTR(v1, top(stack));
+    TEST_ASSERT_EQUAL_INT(1, *(int *)top(stack));
+    free(v1);
+    stack = pop(stack);
+
+    TEST_ASSERT_NULL(stack);
+}
+
+void test_topOnEmptyStackReturnsNull(void)
+{
+    StackNode *stack = NULL;
+    TEST_ASSERT_NULL(top(stack));
+}
+
+void test_clearStackFreesAllNodes(void)
+{
+    StackNode *stack = NULL;
+
+    int a = 11;
+    int b = 22;
+    int c = 33;
+
+    stack = push(stack, &a);
+    stack = push(stack, &b);
+    stack = push(stack, &c);
+
+    TEST_ASSERT_NOT_NULL(stack);
+    TEST_ASSERT_EQUAL_INT(33, *(int *)top(stack));
+
+    clearStack(stack);
+
+    stack = NULL;
+
+
+
+}
+
+void setUp(void)
+{
+  
+}
+
+void tearDown(void)
+{
+  
+}
+
+int main(void)
+{
+    UNITY_BEGIN();
+
+    printf("\n============================\nStack tests\n============================\n");
+
+    RUN_TEST(test_pushAndTopReturnLastPushed);
+    RUN_TEST(test_popOnEmptyStackReturnsNull);
+    RUN_TEST(test_pushAndPopLifoOrder);
+    RUN_TEST(test_topOnEmptyStackReturnsNull);
+    RUN_TEST(test_clearStackFreesAllNodes);
+
+    return UNITY_END();
+}
diff --git a/test_stack.exe b/test_stack.exe
new file mode 100644
index 0000000..92e047f
Binary files /dev/null and b/test_stack.exe differ
diff --git a/test_tree.c b/test_tree.c
new file mode 100644
index 0000000..6c1ab69
--- /dev/null
+++ b/test_tree.c
@@ -0,0 +1,118 @@
+#include "unity.h"
+#include "bintree.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+static int compare(const void *a, const void *b)
+{
+    return (*(int *)a > *(int *)b) - (*(int *)a < *(int *)b);
+}
+
+void setUp(void) { }
+void tearDown(void) { }
+
+void test_addToTree_single_element(void)
+{
+    TreeNode *root = NULL;
+    int value = 10;
+    int dup;
+
+    root = addToTree(root, &value, sizeof(int), compare, &dup);
+
+    TEST_ASSERT_NOT_NULL(root);
+    TEST_ASSERT_EQUAL_INT(10, *(int*)root->data);
+    TEST_ASSERT_EQUAL_INT(0, dup);
+
+    clearTree(root);
+}
+
+void test_addToTree_multiple_elements_and_size(void)
+{
+    TreeNode *root = NULL;
+    int values[] = {5, 3, 7, 1, 4};
+    int dup;
+
+    for (int i = 0; i < 5; i++)
+        root = addToTree(root, &values[i], sizeof(int), compare, &dup);
+
+    TEST_ASSERT_EQUAL_UINT(5, treeSize(root));
+
+    clearTree(root);
+}
+
+void test_addToTree_duplicate_detection(void)
+{
+    TreeNode *root = NULL;
+    int val = 42;
+    int dup;
+
+    root = addToTree(root, &val, sizeof(int), compare, &dup);
+    TEST_ASSERT_EQUAL_INT(0, dup);
+
+    root = addToTree(root, &val, sizeof(int), compare, &dup);
+    TEST_ASSERT_EQUAL_INT(1, dup);
+
+    clearTree(root);
+}
+
+void test_treeSize_empty_tree_detection(void)
+{
+    TEST_ASSERT_EQUAL_UINT(0, treeSize(NULL));
+}
+
+void test_nextTreeData_returns_inorder(void)
+{
+    TreeNode *root = NULL;
+    int values[] = {5, 3, 7, 2, 4, 6, 8};
+
+    for (int i = 0; i < 7; i++)
+        root = addToTree(root, &values[i], sizeof(int), compare, NULL);
+
+    int expected[] = {2,3,4,5,6,7,8};
+
+    int idx = 0;
+    void *p = nextTreeData(root);
+
+    while (p != NULL)
+    {
+        TEST_ASSERT_EQUAL_INT(expected[idx], *(int*)p);
+        idx++;
+        p = nextTreeData(NULL);
+    }
+
+    TEST_ASSERT_EQUAL_INT(7, idx);
+
+    clearTree(root);
+}
+
+void test_treeSize_returns_correct_size()
+{
+    TreeNode *root = NULL;
+    int values[] = {8, 3, 10, 1, 6, 14};
+
+    for (int i = 0; i < 6; i++)
+        root = addToTree(root, &values[i], sizeof(int), compare, NULL);
+
+    TEST_ASSERT_EQUAL_UINT(6, treeSize(root));
+
+    clearTree(root);
+    root = NULL;
+
+    TEST_ASSERT_EQUAL_UINT(0, treeSize(root));
+}
+
+int main(void)
+{
+    UNITY_BEGIN();
+
+    printf("\n============================\n Bintree tests\n============================\n");
+
+    RUN_TEST(test_addToTree_single_element);
+    RUN_TEST(test_addToTree_multiple_elements_and_size);
+    RUN_TEST(test_addToTree_duplicate_detection);
+    RUN_TEST(test_treeSize_empty_tree_detection);
+    RUN_TEST(test_nextTreeData_returns_inorder);
+    RUN_TEST(test_treeSize_returns_correct_size);
+
+    return UNITY_END();
+}
diff --git a/test_tree.exe b/test_tree.exe
new file mode 100644
index 0000000..77ab89a
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diff --git a/timer.o b/timer.o
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index 0000000..5af0f96
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