diff --git a/bintree.c b/bintree.c
index 5cf82a9..642e3fc 100644
--- a/bintree.c
+++ b/bintree.c
@@ -1,36 +1,129 @@
+#include <stdlib.h>
 #include <string.h>
-#include "stack.h"
 #include "bintree.h"
 
-//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. */
+// --------------------------
+// Hilfsfunktion für Vergleich von unsigned int
+// --------------------------
+static int compareUint(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;
+}
 
-// 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).
+// --------------------------
+// addToTree
+// --------------------------
 TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
 {
+    if (!compareFct)
+        compareFct = compareUint;
 
+    if (!root)
+    {
+        TreeNode *node = malloc(sizeof(TreeNode));
+        if (!node) return NULL;
+        node->data = malloc(dataSize);
+        if (!node->data)
+        {
+            free(node);
+            return NULL;
+        }
+        memcpy(node->data, data, dataSize);
+        node->left = node->right = NULL;
+        if (isDuplicate) *isDuplicate = 0;
+        return node;
+    }
+
+    int cmp = compareFct(data, root->data);
+    if (cmp == 0)
+    {
+        if (isDuplicate) *isDuplicate = 1;
+        return root;
+    }
+    else if (cmp < 0)
+        root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
+    else
+        root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
+
+    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)
-{
-
-}
-
-// Releases all memory resources (including data copies).
+// --------------------------
+// clearTree
+// --------------------------
 void clearTree(TreeNode *root)
 {
-
+    if (!root) return;
+    clearTree(root->left);
+    clearTree(root->right);
+    free(root->data);
+    free(root);
 }
 
-// Returns the number of entries in the tree given by root.
+// --------------------------
+// treeSize
+// --------------------------
 unsigned int treeSize(const TreeNode *root)
 {
+    if (!root) return 0;
+    return 1 + treeSize(root->left) + treeSize(root->right);
+}
 
+// --------------------------
+// nextTreeData (In-Order Traversal mit Stack) – minimal
+// --------------------------
+#include "stack.h"
+void *nextTreeData(TreeNode *root)
+{
+    static StackNode *stack = NULL;
+    static TreeNode *current = NULL;
+
+    if (root) current = root;
+
+    while (current)
+    {
+        stack = push(stack, current);
+        current = current->left;
+    }
+
+    if (!stack) return NULL;
+
+    TreeNode *node = top(stack);
+    stack = pop(stack);
+
+    current = node->right;
+    return node->data;
+}
+
+// --------------------------
+// Zusätzliche Hilfsfunktion contains für numbers.c
+// --------------------------
+int contains(TreeNode *root, unsigned int value)
+{
+    if (!root) return 0;
+    unsigned int nodeValue = *(unsigned int *)root->data;
+    if (value == nodeValue) return 1;
+    if (value < nodeValue) return contains(root->left, value);
+    return contains(root->right, value);
+}
+
+// --------------------------
+// Hilfsfunktion insert für numbers.c
+// --------------------------
+TreeNode* insert(TreeNode *root, unsigned int value)
+{
+    int isDup = 0;
+    return addToTree(root, &value, sizeof(unsigned int), compareUint, &isDup);
+}
+
+// --------------------------
+// Hilfsfunktion freeTree für numbers.c
+// --------------------------
+void freeTree(TreeNode *root)
+{
+    clearTree(root);
 }
\ No newline at end of file
diff --git a/bintree.o b/bintree.o
new file mode 100644
index 0000000..a9c7b28
Binary files /dev/null and b/bintree.o differ
diff --git a/doble.exe b/doble.exe
new file mode 100644
index 0000000..de16a86
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..9eda5f3
Binary files /dev/null and b/doble_initial.exe differ
diff --git a/highscore.o b/highscore.o
new file mode 100644
index 0000000..21be6ce
Binary files /dev/null and b/highscore.o differ
diff --git a/highscores.txt b/highscores.txt
index 4edd5a7..87fa3e1 100644
--- a/highscores.txt
+++ b/highscores.txt
@@ -1 +1,10 @@
+player_name1;19827
+player_name3;6985
+jannik;5979
+jannik;4991
+jannik;4980
 player1;3999
+player_name;3995
+player_name2;3994
+player_name1;3993
+player_name3;3990
diff --git a/main.o b/main.o
new file mode 100644
index 0000000..30eb06f
Binary files /dev/null and b/main.o differ
diff --git a/makefile b/makefile
index 1f15f75..81649ae 100644
--- a/makefile
+++ b/makefile
@@ -16,34 +16,68 @@ raylibfolder = ./raylib
 unityfolder = ./unity
 
 # --------------------------
-# Initiales Programm bauen (zum ausprobieren)
+# Hauptprogramm bauen
 # --------------------------
-doble_initial:
-	$(CC) -o doble_initial $(BINARIES)/libdoble_complete.a
 
-# --------------------------
-# Selbst implementiertes Programm bauen
-# --------------------------
 program_obj_files = stack.o bintree.o numbers.o timer.o highscore.o
 
-doble : main.o $(program_obj_files)
+doble: main.o $(program_obj_files)
 	$(CC) $(FLAGS) $^ -o doble
 
+main.o: main.c
+	$(CC) -c $(FLAGS) main.c -o main.o
+
 $(program_obj_filesobj_files): %.o: %.c
 	$(CC) -c $(FLAGS) $^ -o $@
 
 # --------------------------
 # Unit Tests
 # --------------------------
-unitTests:
-	echo "needs to be implemented"
+
+unitTests: test_stack test_numbers
+	./test_stack
+	./test_numbers
+
+# --- Test Stack ---
+test_stack: test_stack.o stack.o
+	$(CC) $(FLAGS) $^ -o test_stack
+
+test_stack.o: test_stack.c stack.h
+	$(CC) -c $(FLAGS) test_stack.c -o test_stack.o
+
+# --- Test Numbers ---
+test_numbers: test_numbers.o numbers.o bintree.o stack.o
+	$(CC) $(FLAGS) $^ -o test_numbers
+
+test_numbers.o: test_numbers.c numbers.h
+	$(CC) -c $(FLAGS) test_numbers.c -o test_numbers.o
+
+# --------------------------
+# Objektdateien
+# --------------------------
+
+stack.o: stack.c stack.h
+	$(CC) -c $(FLAGS) stack.c -o stack.o
+
+bintree.o: bintree.c bintree.h stack.h
+	$(CC) -c $(FLAGS) bintree.c -o bintree.o
+
+numbers.o: numbers.c numbers.h bintree.h
+	$(CC) -c $(FLAGS) numbers.c -o numbers.o
+
+timer.o: timer.c timer.h
+	$(CC) -c $(FLAGS) timer.c -o timer.o
+
+highscore.o: highscore.c highscore.h
+	$(CC) -c $(FLAGS) highscore.c -o highscore.o
 
 # --------------------------
 # Clean
 # --------------------------
+
 clean:
 ifeq ($(OS),Windows_NT)
-	del /f *.o doble
+	del /f *.o doble test_stack test_numbers
 else
-	rm -f *.o doble
+	rm -f *.o doble test_stack test_numbers
 endif
\ No newline at end of file
diff --git a/numbers.c b/numbers.c
index f59d9a2..f10610e 100644
--- a/numbers.c
+++ b/numbers.c
@@ -5,22 +5,83 @@
 #include "numbers.h"
 #include "bintree.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)
-{
-
+// Hilfsfunktion zum Vergleichen von ints für Baum
+static int compareInt(const void *a, const void *b) {
+    return (*(int*)a - *(int*)b);
 }
 
-// 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)
-{
+// Vergleichsfunktion für qsort (unsigned int, überlauf-sicher)
+static int compareUnsigned(const void *a, const void *b) {
+    unsigned int ua = *(unsigned int*)a;
+    unsigned int ub = *(unsigned int*)b;
 
+    if (ua < ub) return -1;
+    if (ua > ub) return 1;
+    return 0;
+}
+
+// Hilfsfunktion: Prüft, ob Wert schon im Baum ist
+static int contains(TreeNode *root, unsigned int value) {
+    if (!root) return 0;
+    unsigned int val = *(unsigned int*)root->data;
+    if (val == value) return 1;
+    if (value < val) return contains(root->left, value);
+    return contains(root->right, value);
+}
+
+// Erzeugt ein Array von len Zahlen zwischen 1 und 2*len, alle einzigartig,
+// außer eine Zahl wird dupliziert.
+unsigned int *createNumbers(unsigned int len) {
+    if (len == 0) return NULL;
+
+    unsigned int *numbers = malloc(len * sizeof(unsigned int));
+    if (!numbers) return NULL;
+
+    TreeNode *tree = NULL;
+    srand((unsigned int)time(NULL));
+
+    for (unsigned int i = 0; i < len - 1; i++) {  // alle außer die Duplikate
+        unsigned int value;
+        do {
+            value = rand() % (2 * len) + 1;
+        } while (contains(tree, value));
+
+        int isDup = 0;
+        tree = addToTree(tree, &value, sizeof(value), compareInt, &isDup);
+        numbers[i] = value;
+    }
+
+    // Dupliziere zufällig eine Zahl
+    unsigned int dupIndex = rand() % (len - 1);
+    numbers[len - 1] = numbers[dupIndex];
+
+    // Speicher freigeben
+    clearTree(tree);
+
+    return numbers;
+}
+
+// Sortiert das Array und findet die einzige doppelte Zahl
+unsigned int getDuplicate(const unsigned int *numbers, unsigned int len) {
+    if (!numbers || len < 2) return 0;
+
+    // Kopiere Array, da wir sortieren müssen
+    unsigned int *copy = malloc(len * sizeof(unsigned int));
+    if (!copy) return 0;
+    memcpy(copy, numbers, len * sizeof(unsigned int));
+
+    // qsort verwenden
+    qsort(copy, len, sizeof(unsigned int), compareUnsigned);
+
+    // Durchlauf und Nachbarn vergleichen
+    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;
 }
\ No newline at end of file
diff --git a/numbers.o b/numbers.o
new file mode 100644
index 0000000..1135c4e
Binary files /dev/null and b/numbers.o differ
diff --git a/stack.c b/stack.c
index e3a90d4..8f1d1b6 100644
--- a/stack.c
+++ b/stack.c
@@ -1,33 +1,38 @@
 #include <stdlib.h>
 #include "stack.h"
 
-//TODO: grundlegende Stackfunktionen implementieren:
-/*  * `push`: legt ein Element oben auf den Stack,
-    * `pop`: entfernt das oberste Element,
-    * `top`: liefert das oberste Element zurück,
-    * `clearStack`: gibt den gesamten Speicher frei. */
+// Pushes data onto the stack and returns new stack top
+StackNode *push(StackNode *stack, void *data) {
+    StackNode *node = malloc(sizeof(StackNode));
+    if (!node) return stack;  // allocation failed → leave stack unchanged
 
-// Pushes data as pointer onto the stack.
-StackNode *push(StackNode *stack, void *data)
-{
+    node->data = data;
+    node->next = stack;
 
+    return node; // new top
 }
 
-// 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)
-{
+// Removes the top element, frees node (NOT data), returns new top
+StackNode *pop(StackNode *stack) {
+    if (stack == NULL) return NULL;
 
+    StackNode *next = stack->next;
+    free(stack);
+
+    return next; // new top
 }
 
-// Returns the data of the top element.
-void *top(StackNode *stack)
-{
-
+// Returns data of top node or NULL
+void *top(StackNode *stack) {
+    if (!stack) return NULL;
+    return stack->data;
 }
 
-// Clears stack and releases all memory.
-void clearStack(StackNode *stack)
-{
-
-}
\ No newline at end of file
+// Frees entire stack (NOT data!)
+void clearStack(StackNode *stack) {
+    while (stack != NULL) {
+        StackNode *next = stack->next;
+        free(stack);
+        stack = next;
+    }
+}
diff --git a/stack.h b/stack.h
index f7d542d..0d3f1e8 100644
--- a/stack.h
+++ b/stack.h
@@ -1,19 +1,23 @@
 #ifndef STACK_H
 #define STACK_H
 
-/* A stack is a special type of queue which uses the LIFO (last in, first out) principle. 
-This means that with each new element all other elements are pushed deeper into the stack. 
-The latest element is taken from the stack. */
+/* A stack is a special type of queue which uses the LIFO (last in, first out) principle.
+   This means that with each new element all other elements are pushed deeper into the stack.
+   The latest element is taken from the stack. */
 
 #include <stdlib.h>
 
-//TODO: passenden Datentyp als struct anlegen
+// passenden Datentyp als struct anlegen
+typedef struct StackNode {
+    void *data;               // Zeiger auf beliebige Daten
+    struct StackNode *next;   // Zeiger auf das nächste Element im Stack
+} StackNode;
 
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);
 
-// Deletes the top element of the stack (latest added element) and releases its memory. (Pointer to data has to be
-// freed by caller.)
+// 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);
 
 // Returns the data of the top element.
diff --git a/stack.o b/stack.o
new file mode 100644
index 0000000..4cc2f4b
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..11c072c
--- /dev/null
+++ b/test_numbers.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "numbers.h"
+
+int main(void)
+{
+    printf("=== TEST: createNumbers & getDuplicate ===\n");
+
+    unsigned int len = 20;
+    unsigned int *arr = createNumbers(len);
+
+    if (!arr)
+    {
+        printf("FAILED: createNumbers returned NULL\n");
+        return 1;
+    }
+
+    printf("Array created: ");
+    for (unsigned int i = 0; i < len; i++)
+        printf("%u ", arr[i]);
+    printf("\n");
+
+    unsigned int dup = getDuplicate(arr, len);
+
+    if (dup == 0)
+    {
+        printf("FAILED: getDuplicate returned 0 (no duplicate found)\n");
+        free(arr);
+        return 1;
+    }
+
+    // Count occurrences manually as safety check
+    unsigned int count = 0;
+    for (unsigned int i = 0; i < len; i++)
+        if (arr[i] == dup)
+            count++;
+
+    if (count != 2)
+    {
+        printf("FAILED: duplicate=%u occurs %u times (expected 2)\n", dup, count);
+        free(arr);
+        return 1;
+    }
+
+    printf("SUCCESS: duplicate number is %u and appears exactly twice.\n", dup);
+
+    free(arr);
+    return 0;
+}
\ No newline at end of file
diff --git a/test_numbers.exe b/test_numbers.exe
new file mode 100644
index 0000000..2d91b7b
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..bebcdf2
--- /dev/null
+++ b/test_stack.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "stack.h"
+
+int main() {
+    StackNode *stack = NULL;
+
+    // Einige Integer dynamisch alloziieren
+    int *a = malloc(sizeof(int));
+    int *b = malloc(sizeof(int));
+    int *c = malloc(sizeof(int));
+    *a = 10; *b = 20; *c = 30;
+
+    stack = push(stack, a);
+    stack = push(stack, b);
+    stack = push(stack, c);
+
+    // Test top()
+    printf("Top = %d (expected 30)\n", *(int *)top(stack));
+
+    // pop()
+    stack = pop(stack); // removed 30
+    free(c);            // data gehört Benutzer!
+
+    printf("Top = %d (expected 20)\n", *(int *)top(stack));
+
+    stack = pop(stack); free(b);  // removed 20
+    stack = pop(stack); free(a);  // removed 10
+
+    // stack should now be empty
+    if (stack == NULL) {
+        printf("Stack empty ok\n");
+    } else {
+        printf("Error: stack not empty!\n");
+    }
+
+    // Cleanup just in case
+    clearStack(stack);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/test_stack.exe b/test_stack.exe
new file mode 100644
index 0000000..50030d5
Binary files /dev/null and b/test_stack.exe differ
diff --git a/timer.o b/timer.o
new file mode 100644
index 0000000..3cf4e85
Binary files /dev/null and b/timer.o differ