diff --git a/bintree.c b/bintree.c
index 54f423e..a843c1d 100644
--- a/bintree.c
+++ b/bintree.c
@@ -1,8 +1,10 @@
 #include <string.h>
+#include <stdio.h>
 #include "stack.h"
 #include "bintree.h"
 
 static StackNode *stack;
+static TreeNode *tree = NULL;
 // TODO: binären Suchbaum implementieren
 /*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
  * `clearTree`: gibt den gesamten Baum frei (rekursiv),
@@ -17,19 +19,29 @@ TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFc
     {
         TreeNode *newNode = malloc(sizeof(TreeNode));
         newNode->data = malloc(dataSize);
-        newNode->data = data;
+        memcpy(newNode->data, data, dataSize);
         newNode->left = NULL;
         newNode->right = NULL;
         return newNode;
     }
-    if (compareFct(root->data, data) < 0)
+    
+    int cmp = compareFct(root->data, data);
+    if (cmp < 0)
     {
         root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
     }
-    else if (compareFct(root->data, data) > 0)
+    else if (cmp > 0)
     {
         root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
     }
+    else
+    {
+        if (isDuplicate != NULL)
+        {
+            *isDuplicate = 1; // Mark as duplicate if needed.
+        }
+    }
+
     return root;
 }
 
@@ -38,11 +50,24 @@ 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)
 {
+    if (root != NULL)
+    {
+        clearStack(stack);
+        buildStack(root);
+    }
+
+    if(stack != NULL)
+    {
+        
+        void* data = top(stack);
+        stack = pop(stack);
+        return data;
+    }
+
     return NULL;
 
 }
 
-
 // Releases all memory resources (including data copies).
 void clearTree(TreeNode *root)
 {
@@ -70,4 +95,17 @@ void clearTree(TreeNode *root)
 unsigned int treeSize(const TreeNode *root)
 {
     return root == NULL ? 0 : treeSize(root->left) + treeSize(root->right) + 1;
-}
\ No newline at end of file
+}
+
+void buildStack(TreeNode *root)
+{
+    
+    if (root == NULL)
+    {
+       return; 
+    }
+        
+    buildStack(root->left);   // biggest first
+    stack = push(stack, root->data);                 // push
+    buildStack(root->right); 
+}
diff --git a/bintree.h b/bintree.h
index 25e16b2..f7be496 100644
--- a/bintree.h
+++ b/bintree.h
@@ -24,4 +24,6 @@ void clearTree(TreeNode *root);
 // Returns the number of entries in the tree given by root.
 unsigned int treeSize(const TreeNode *root);
 
+void buildStack(TreeNode *root);
+
 #endif
\ No newline at end of file
diff --git a/highscore.c b/highscore.c
index fe8a458..8d3ef5c 100644
--- a/highscore.c
+++ b/highscore.c
@@ -79,6 +79,8 @@ int addHighscore(const char *name, double timeInSeconds, unsigned int len)
 {
     HighscoreEntry entry = createHighscoreEntry(name, calculateScore(timeInSeconds, len));
     highscoreTree = addToTree(highscoreTree, &entry, sizeof(entry), compareHighscoreEntries, NULL);
+    //HighscoreEntry *temp = highscoreTree->data;
+    //printf("%s%d\n", temp->name, temp->score);
 
     return entry.score;
 }
diff --git a/highscores.txt b/highscores.txt
index e69de29..d1dcaac 100644
--- a/highscores.txt
+++ b/highscores.txt
@@ -0,0 +1,5 @@
+nick;9963
+nick;9946
+simon;4965
+alex;2996
+simon;2996
diff --git a/makefile b/makefile
index 5cca804..890cc50 100644
--- a/makefile
+++ b/makefile
@@ -35,7 +35,7 @@ $(program_obj_filesobj_files): %.o: %.c
 # --------------------------
 # Unit Tests
 # --------------------------
-unitTests: stack.o test_stack.c $(unityfolder)/unity.c
+stackTests: stack.o test_stack.c $(unityfolder)/unity.c
 	$(CC) $(FLAGS) -I$(unityfolder) -o runStackTest test_stack.c stack.o $(unityfolder)/unity.c
 
 # --------------------------
diff --git a/stack.c b/stack.c
index 5a10712..8762fa3 100644
--- a/stack.c
+++ b/stack.c
@@ -10,46 +10,24 @@
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data)
 {
-    StackNode *tempNode, *newNode;
-
-    newNode = malloc(sizeof(StackNode));
-    newNode->value = data;
-    newNode->next = NULL;
-
-    if (stack == NULL)
-    {
-        stack = newNode;
-        return stack;
-    }
-
-    tempNode = stack;
-    while (tempNode->next != NULL)
-    {
-        tempNode = tempNode->next;
-    }
-    tempNode->next = newNode;
-
-    return stack;
+    StackNode *newNode = malloc(sizeof(StackNode));
+    newNode->data = data;
+    newNode->next = stack;  // Set the new node's next pointer to the current top of the stack.
+    return newNode;  // Return the new node as the top of the stack.
 }
 
 // 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)
 {
-    StackNode *tempNode;
-
     if (stack == NULL)
     {
-        return stack;
+        return NULL;  // Nothing to pop if stack is empty.
     }
 
-    tempNode = stack;
-    while (tempNode->next->next != NULL)
-    {
-        tempNode = tempNode->next;
-    }
-    free(tempNode->next);
-    tempNode->next = NULL;
+    StackNode *tempNode = stack;
+    stack = stack->next;  // Move the stack pointer to the next node.
+    free(tempNode);  // Free the old top node.
 
     return stack;
 }
@@ -57,35 +35,19 @@ StackNode *pop(StackNode *stack)
 // Returns the data of the top element.
 void *top(StackNode *stack)
 {
-    StackNode *tempNode;
-
     if (stack == NULL)
     {
-        return NULL;
+        return NULL;  // Return NULL if stack is empty.
     }
 
-    tempNode = stack;
-    while (tempNode->next != NULL)
-    {
-        tempNode = tempNode->next;
-    }
-
-    return &tempNode->value;
+    return stack->data;  // Return the value of the top node.
 }
 
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
-    StackNode *tempNode;
-
-    if (stack == NULL)
+    while (stack != NULL)
     {
-        return;
-    }
-
-    tempNode = stack;
-    while (tempNode != NULL)
-    {
-        tempNode = pop(tempNode);
+        stack = pop(stack);  // Pop each element and free memory.
     }
 }
\ No newline at end of file
diff --git a/stack.h b/stack.h
index 0d1130c..69ac923 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 {
-    void *value;
+    void *data;
     struct Node* next;
 } StackNode;
 
diff --git a/stackTest.c b/stackTest.c
new file mode 100644
index 0000000..971b172
--- /dev/null
+++ b/stackTest.c
@@ -0,0 +1,100 @@
+#include "unity.h"
+#include "stack.h"  // Stack-Header-Datei
+#include <stdlib.h>
+
+// Test Setup and Teardown Functions
+void setUp(void) {
+    // Setup code (falls notwendig, wie Initialisierungen)
+}
+
+void tearDown(void) {
+    // Cleanup code (falls notwendig)
+}
+
+// Test for push operation
+void test_push(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Check if the stack is not empty
+    TEST_ASSERT_NOT_NULL(stack);
+
+    // Check if the top element is correct
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(20, *topData);  // The last pushed element should be on top
+}
+
+// Test for pop operation
+void test_pop(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Pop the top element
+    stack = pop(stack);
+
+    // Check if the top element is now the first pushed element
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(10, *topData);  // After popping, the first element should be on top
+
+    // Pop the last element
+    stack = pop(stack);
+
+    // Check if the stack is empty now
+    TEST_ASSERT_NULL(stack);  // Stack should be NULL now
+}
+
+// Test for top operation
+void test_top(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Check the top element
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(20, *topData);  // The top element should be 20 (last pushed)
+
+    // Pop the top element and check the new top
+    stack = pop(stack);
+    topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(10, *topData);  // Now the top element should be 10
+}
+
+// Test for clearStack operation
+void test_clearStack(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Clear the stack
+    clearStack(stack);
+
+    // The stack should be empty now
+    TEST_ASSERT_NULL(stack);  // Stack should be NULL
+}
+
+// Run all tests
+int main(void) {
+    UNITY_BEGIN();
+
+    // Run the individual test functions
+    RUN_TEST(test_push);
+    RUN_TEST(test_pop);
+    RUN_TEST(test_top);
+    RUN_TEST(test_clearStack);
+
+    return UNITY_END();
+}
diff --git a/test_stack.c b/test_stack.c
index 7e70b58..c611dba 100644
--- a/test_stack.c
+++ b/test_stack.c
@@ -3,16 +3,33 @@
 #include "stack.h"
 #include "unity.h"
 
-void test_push(void)
+void test_push(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Check if the stack is not empty
+    TEST_ASSERT_NOT_NULL(stack);
+
+    // Check if the top element is correct
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(20, *topData);  // The last pushed element should be on top
+}
+
+void test_push1(void)
 {
-    StackNode *testNode;
+    StackNode *testNode = NULL;
     int data = 1;
 
     // Test für leeren Stack
-    testNode = push(NULL, &data);
+    testNode = push(testNode, &data);
     TEST_ASSERT_NOT_NULL(&testNode);
     TEST_ASSERT_NULL(testNode->next);
-    TEST_ASSERT_EQUAL_INT(1, testNode->value);
+    int *temp = testNode->data;
+    TEST_ASSERT_EQUAL_INT(1, *temp);
 
     data = 2;
 
@@ -21,26 +38,53 @@ void test_push(void)
     TEST_ASSERT_NOT_NULL(&testNode);
     TEST_ASSERT_NOT_NULL(testNode->next);
     TEST_ASSERT_NULL(testNode->next->next);
-    TEST_ASSERT_EQUAL_INT(1, testNode->value);
-    TEST_ASSERT_EQUAL_INT(2, testNode->next->value);
+    temp = testNode->data;
+    TEST_ASSERT_EQUAL_INT(2, *temp);
+    testNode = testNode->next;
+    temp = testNode->data;
+    TEST_ASSERT_EQUAL_INT(1, *temp);
 }
 
-StackNode* setup(void *value, StackNode* next) {
+StackNode* setup(void *data, StackNode* next) {
     StackNode* node = malloc(sizeof(StackNode)); // allocate memory on heap
     if (node == NULL) {
         perror("malloc failed");
         exit(EXIT_FAILURE); // or handle the error differently
     }
-    node->value = value;
+    node->data = data;
     node->next = next;
     return node;
 }
+void test_pop(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
 
-void test_pop(void)
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Pop the top element
+    stack = pop(stack);
+
+    // Check if the top element is now the first pushed element
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(10, *topData);  // After popping, the first element should be on top
+
+    // Pop the last element
+    stack = pop(stack);
+
+    // Check if the stack is empty now
+    TEST_ASSERT_NULL(stack);  // Stack should be NULL now
+}
+void test_pop2(void)
 {   
-    StackNode* node2 = setup(3, NULL);
-    StackNode* node1 = setup(2, node2);
-    StackNode* header = setup(1, node1);
+    int x,y,z;
+    x = 1;
+    y = 2;
+    z = 3;
+    StackNode* node2 = setup(&z, NULL);
+    StackNode* node1 = setup(&y, node2);
+    StackNode* header = setup(&x, node1);
     StackNode* temp;
 
     temp = pop(header);
@@ -56,21 +100,62 @@ void test_pop(void)
     TEST_ASSERT_NULL(node1->next);
 }
 
-void test_top(void)
+void test_top(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Check the top element
+    int *topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(20, *topData);  // The top element should be 20 (last pushed)
+
+    // Pop the top element and check the new top
+    stack = pop(stack);
+    topData = top(stack);
+    TEST_ASSERT_EQUAL_INT(10, *topData);  // Now the top element should be 10
+}
+
+void test_top2(void)
 {
-    StackNode* node2 = setup(3, NULL);
-    StackNode* node1 = setup(2, node2);
-    StackNode* header = setup(1, node1);
+    int x,y,z;
+    x = 1;
+    y = 2;
+    z = 3;
+    StackNode* node2 = setup(&z, NULL);
+    StackNode* node1 = setup(&y, node2);
+    StackNode* header = setup(&x, node1);
 
     int data = *(int *)top(header);
-    TEST_ASSERT_EQUAL_INT(node2->value, data);
+    TEST_ASSERT_EQUAL_INT(node2->data, data);
+}
+
+void test_clearStack(void) {
+    StackNode *stack = NULL;
+    int data1 = 10, data2 = 20;
+
+    // Push elements to the stack
+    stack = push(stack, &data1);
+    stack = push(stack, &data2);
+
+    // Clear the stack
+    clearStack(stack);
+
+    // The stack should be empty now
+    TEST_ASSERT_NULL(stack);  // Stack should be NULL
 }
 
 void test_clear()
 {
-    StackNode* node2 = setup(3, NULL);
-    StackNode* node1 = setup(2, node2);
-    StackNode* header = setup(1, node1);
+    int x,y,z;
+    x = 1;
+    y = 2;
+    z = 3;
+    StackNode* node2 = setup(&z, NULL);
+    StackNode* node1 = setup(&y, node2);
+    StackNode* header = setup(&x, node1);
     StackNode* temp;
     
     clearStack(header);
@@ -106,7 +191,7 @@ int main()
     RUN_TEST(test_push);
     RUN_TEST(test_pop);
     RUN_TEST(test_top);
-    RUN_TEST(test_clear);
+    RUN_TEST(test_clearStack);
 
     return UNITY_END();
 }
\ No newline at end of file