restructure and add ipi texs

ws2019/ipi/uebungen/cpp_headers/Stack.hh

@@ -0,0 +1,12 @@
+template<class T>
+class Stack : private DLList<T> {
+public :
+  // Default-Konstruktoren + Zuweisung OK
+
+  bool empty () {return DLList<T>::empty();}
+  void push (T t) {
+    this->insert(DLList<T>::begin(),t);
+  }
+  T top () {return *DLList<T>::begin();}
+  void pop () {this->erase(DLList<T>::begin());}
+} ;