updating to newer version

Startcode/stack.h

@@ -0,0 +1,25 @@
+#ifndef STACK_H
+#define STACK_H
+
+/* A stack is a special type of queue which uses the LIFO (last in, first out) principle. 
+This means that with each new element all other elements are pushed deeper into the stack. 
+The latest element is taken from the stack. */
+
+#include <stdlib.h>
+
+//TODO: passenden Datentyp als struct anlegen
+
+// Pushes data as pointer onto the stack.
+StackNode *push(StackNode *stack, void *data);
+
+// 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);
+
+// Returns the data of the top element.
+void *top(StackNode *stack);
+
+// Clears stack and releases all memory.
+void clearStack(StackNode *stack);
+
+#endif