diff --git a/stack.c b/stack.c
index e3a90d4..4057a99 100644
--- a/stack.c
+++ b/stack.c
@@ -8,9 +8,29 @@
     * `clearStack`: gibt den gesamten Speicher frei. */
 
 // Pushes data as pointer onto the stack.
+static StackNode *createEmptyElement()
+{
+    return malloc(sizeof(StackNode));
+}
 StackNode *push(StackNode *stack, void *data)
 {
-
+    StackNode *newElement = createEmptyElement();
+    newElement->data = data;
+    newElement->next = NULL;
+    if (stack == NULL)
+    {
+        stack = newElement;
+    }
+    else
+    {
+        StackNode *currentElement = stack;
+        while(currentElement->next != NULL)
+        {
+            currentElement = currentElement->next;
+        }
+        currentElement->next = newElement;
+    return stack;
+    }
 }
 
 // Deletes the top element of the stack (latest added element) and releases its memory. (Pointer to data has to be
diff --git a/stack.h b/stack.h
index f7d542d..6d6d48b 100644
--- a/stack.h
+++ b/stack.h
@@ -8,6 +8,11 @@ The latest element is taken from the stack. */
 #include <stdlib.h>
 
 //TODO: passenden Datentyp als struct anlegen
+typedef struct node
+{
+    void *data;
+    struct node* next;
+}StackNode;
 
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);
@@ -22,4 +27,4 @@ void *top(StackNode *stack);
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack);
 
-#endif
+#endif
\ No newline at end of file
diff --git a/test_stack.c b/test_stack.c
new file mode 100644
index 0000000..d472b4b
--- /dev/null
+++ b/test_stack.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "stack.h"
+
+void testPushAddsElementCorrectly(void)
+{
+    int a = 10;
+    StackNode *node = push(NULL, &a);
+
+    TEST_ASSERT_NOT_NULL(node);
+    TEST_ASSERT_EQUAL_INT(a, *((int*)node->data)); //void Zeiger in integer-Zeiger umwandeln
+}
+
+int main(void)
+{
+    UNITY_BEGIN();
+    RUN_TEST(testPushAddsElementCorrectly);
+    return UNITY_END();
+}
\ No newline at end of file