restructure and add ipi texs

ws2019/ipi/uebungen/cpp_headers/fakultaetiter.cc

@@ -0,0 +1,16 @@
+#include "fcpp.hh"
+
+int fakIter (int produkt, int zaehler, int ende)
+{
+  return cond( zaehler>ende,
+	       produkt,
+	       fakIter(produkt*zaehler,zaehler+1,ende) );
+}
+int fakultaet (int n)
+{
+  return fakIter(1,1,n);
+}
+int main ()
+{
+  return print(fakultaet(5));
+}