diff --git a/stack.c b/stack.c
index e3a90d4..c78727b 100644
--- a/stack.c
+++ b/stack.c
@@ -10,7 +10,10 @@
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data)
 {
-
+    StackNode *top = malloc(sizeof(StackNode));
+    top->next= stack;
+    top->data= data;
+    return top;
 }
 
 // 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..a9d2e58 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 StackNode
+{
+    void *data;
+    struct StackNode *next;
+}StackNode;
 
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);