diff --git a/Start_Windows/makefile b/Start_Windows/makefile
index b67312a..b3d0844 100644
--- a/Start_Windows/makefile
+++ b/Start_Windows/makefile
@@ -26,6 +26,9 @@ $(program_obj_filesobj_files): %.o: %.c
 unitTests:
 	echo "needs to be implemented"
 
+stackTests: stack.o stackTests.c $(unityfolder)/unity.c
+	$(CC) $(CFLAGS) -I$(unityfolder) -o runStackTests stackTests.c stack.o $(unityfolder)/unity.c
+
 # --------------------------
 # Clean
 # --------------------------
diff --git a/Start_Windows/stack.c b/Start_Windows/stack.c
index 6383694..a89f014 100644
--- a/Start_Windows/stack.c
+++ b/Start_Windows/stack.c
@@ -10,24 +10,45 @@
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data)
 {
-    
+    StackNode *new=malloc(sizeof(StackNode));
+    if(new ==NULL){
+        return new;
+    }
+    new->data = data;
+    new->dannach = stack;
+    return new;
 }
 
 // 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 *new=malloc(sizeof(StackNode));
+    if(new ==NULL){
+        return new;
+    }
+    new = stack->dannach;
 
+    stack->dannach = NULL;
+    free(stack->data);
+    free(stack);
+    return new;
 }
 
 // Returns the data of the top element.
 void *top(StackNode *stack)
 {
-
+    return stack->data;
 }
 
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
-
+    if(stack == NULL){
+        return;
+    }
+    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 45714c3..ac7f301 100644
--- a/Start_Windows/stack.h
+++ b/Start_Windows/stack.h
@@ -10,9 +10,9 @@ The latest element is taken from the stack. */
 
 
 //TODO: passenden Datentyp als struct anlegen
-typedef struct{
-    int items[MAX_STACK_SIZE];
-    int top;
+typedef struct Stack{
+    void* data ;
+    StackNode* dannach;
 }StackNode;
 
 // Pushes data as pointer onto the stack.
diff --git a/Start_Windows/stackTests.c b/Start_Windows/stackTests.c
new file mode 100644
index 0000000..0a6e4bd
--- /dev/null
+++ b/Start_Windows/stackTests.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include "unity.h"
+#include "stack.h"
+
+
+static void pushVorhandenerStack(){
+    StackNode stack = {(int)1,NULL};
+
+    StackNode *tester = push(&stack,(int)2);
+
+    TEST_ASSERT_EQUAL_INT(tester->data,2);
+    TEST_ASSERT_EQUAL_INT(tester->dannach->data,1);
+}
+
+
+
+int main(){
+    UNITY_BEGIN();
+    printf("\n============================\nStack tests\n============================\n");
+    
+    RUN_TEST(pushVorhandenerStack);
+
+
+    return UNITY_END();
+}
\ No newline at end of file