restructure and add ipi texs

ws2019/ipi/uebungen/cpp_headers/UseRational.cc

@@ -0,0 +1,13 @@
+#include "fcpp.hh"       // fuer print
+#include "Rational.hh"
+#include "Rational.cc"
+
+int main () {
+    Rational p(3,4), q(5,3), r;
+
+    p.print(); q.print();
+    r = (p+q*p)*p*p;
+    r.print();
+    
+    return 0;
+}