diff --git a/stack.c b/stack.c
index e3a90d4..be0f396 100644
--- a/stack.c
+++ b/stack.c
@@ -10,24 +10,44 @@
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data)
 {
+	StackNode* stacknew = malloc(sizeof(StackNode));
 
+	stacknew->value = data;
+	stacknew->prev = stack;
+
+	return stacknew;
 }
 
 // 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 *ptr = stack->prev;
 
+	free(stack);
+	return ptr;
 }
 
 // Returns the data of the top element.
 void *top(StackNode *stack)
 {
 
+    return stack->value;
+
 }
 
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
+    StackNode *ptr = stack;
 
+    while (ptr != NULL) {
+
+        StackNode *prev = ptr->prev;
+
+        free(ptr->value);
+        free(ptr);
+
+        ptr = prev;
+    }
 }
\ No newline at end of file
diff --git a/stack.h b/stack.h
index f7d542d..3f8746e 100644
--- a/stack.h
+++ b/stack.h
@@ -8,6 +8,10 @@ The latest element is taken from the stack. */
 #include <stdlib.h>
 
 //TODO: passenden Datentyp als struct anlegen
+typedef struct  {
+    void* value;
+    StackNode* prev;
+} StackNode;
 
 // Pushes data as pointer onto the stack.
 StackNode *push(StackNode *stack, void *data);