diff --git a/Start_Windows/runStackTests.exe b/Start_Windows/runStackTests.exe
new file mode 100644
index 0000000..cb9a945
Binary files /dev/null and b/Start_Windows/runStackTests.exe differ
diff --git a/Start_Windows/stack.c b/Start_Windows/stack.c
index a89f014..3e4ad18 100644
--- a/Start_Windows/stack.c
+++ b/Start_Windows/stack.c
@@ -23,14 +23,11 @@ StackNode *push(StackNode *stack, void *data)
 // freed by caller.)
 StackNode *pop(StackNode *stack)
 {
-    StackNode *new=malloc(sizeof(StackNode));
-    if(new ==NULL){
-        return new;
+    if(stack == NULL){
+        return NULL;
     }
+    StackNode *new;
     new = stack->dannach;
-
-    stack->dannach = NULL;
-    free(stack->data);
     free(stack);
     return new;
 }
@@ -38,17 +35,19 @@ StackNode *pop(StackNode *stack)
 // 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)
 {
-    if(stack == NULL){
-        return;
+    while (stack != NULL) {
+        StackNode *next = stack->dannach;
+                
+        free(stack);
+        stack = next;
     }
-    clearStack(stack->dannach);
-    free(stack->dannach);
-    free(stack->data);
-    free(stack);
 }
\ No newline at end of file
diff --git a/Start_Windows/stack.h b/Start_Windows/stack.h
index ac7f301..e37cc5a 100644
--- a/Start_Windows/stack.h
+++ b/Start_Windows/stack.h
@@ -8,12 +8,12 @@ The latest element is taken from the stack. */
 
 #include <stdlib.h>
 
-
+typedef struct StackNode StackNode;
 //TODO: passenden Datentyp als struct anlegen
-typedef struct Stack{
-    void* data ;
+struct StackNode {
+    void* data;
     StackNode* dannach;
-}StackNode;
+};
 
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);
diff --git a/Start_Windows/stack.o b/Start_Windows/stack.o
new file mode 100644
index 0000000..022303f
Binary files /dev/null and b/Start_Windows/stack.o differ
diff --git a/Start_Windows/stackTests.c b/Start_Windows/stackTests.c
index 0a6e4bd..365bdbc 100644
--- a/Start_Windows/stackTests.c
+++ b/Start_Windows/stackTests.c
@@ -6,13 +6,94 @@
 #include "stack.h"
 
 
+static void pushNeuerStack(){
+    int wert = 2;
+    StackNode *tester = push(NULL,&wert);
+
+    int gespeicherterWert = *(int*)(tester->data);
+    TEST_ASSERT_EQUAL_INT(*(int*)(tester->data),2);
+    TEST_ASSERT_TRUE(tester->dannach == NULL);
+}
+
 static void pushVorhandenerStack(){
-    StackNode stack = {(int)1,NULL};
+    StackNode *stack = NULL;
 
-    StackNode *tester = push(&stack,(int)2);
+    int a = 1;
+    stack = push(stack, &a);
+
+    int b = 2;
+    stack = push(stack,&b);
+
+    int gespeicherterWert = *(int*)(stack->data);
+    TEST_ASSERT_EQUAL_INT(*(int*)(stack->data),2);
+    TEST_ASSERT_EQUAL_INT(*(int*)(stack->dannach->data),1);
+}
+
+
+void testTop(){
+    StackNode *stack = NULL;
+
+    int a = 1;
+    int b = 2;
+
+    stack = push(stack, &a);
+    stack = push(stack, &b);
+
+    
+    TEST_ASSERT_EQUAL_INT(2, *(int *)top(stack));                   // top sollte b sein
+
+
+}
+
+void testPop(void) {
+    StackNode *stack = NULL;
+
+    int a = 1;
+    int b = 2;
+
+    stack = push(stack, &a);
+    stack = push(stack, &b);
+
+    
+    TEST_ASSERT_EQUAL_INT(2, *(int *)top(stack));                   // top sollte b sein
+
+    stack = pop(stack);
+    TEST_ASSERT_NOT_NULL(stack);
+    TEST_ASSERT_EQUAL_INT(1, *(int *)top(stack));                   // top sollte a sein
+
+    stack = pop(stack);
+    TEST_ASSERT_NULL(stack);                                        // leerer Stack nach pop
+
+}
+
+void testPopLeererStack(void) {
+    StackNode *stack = NULL;
+    stack = pop(stack);
+    TEST_ASSERT_NULL(stack);
+}
+
+void testClearStackAllesFrei(void) {
+    StackNode *stack = NULL;
+
+    int *a = malloc(sizeof(int));
+    int *b = malloc(sizeof(int));
+    *a = 10;
+    *b = 20;
+
+    stack = push(stack, a);
+    stack = push(stack, b);
+
+    clearStack(stack);
+    
+    TEST_ASSERT_TRUE(1); // Wenn kein Crash und Speicher sauber, gilt als bestanden
+}
+
+void setUp(void){
+
+}
+
+void tearDown(void){
 
-    TEST_ASSERT_EQUAL_INT(tester->data,2);
-    TEST_ASSERT_EQUAL_INT(tester->dannach->data,1);
 }
 
 
@@ -21,8 +102,12 @@ int main(){
     UNITY_BEGIN();
     printf("\n============================\nStack tests\n============================\n");
     
+    RUN_TEST(pushNeuerStack);
     RUN_TEST(pushVorhandenerStack);
-
+    RUN_TEST(testTop);
+    RUN_TEST(testPop);
+    RUN_TEST(testPopLeererStack);
+    RUN_TEST(testClearStackAllesFrei);
 
     return UNITY_END();
 }
\ No newline at end of file