In this paper, we describe a non-invasive approach for validation 
of class invariants in C++ applications.  Our approach is fully 
automated so that the user need only supply the class invariants 
for each class hierarchy to be checked and our validator constructs 
an InvariantVisitor, a variation of the Visitor Pattern, and an 
InvariantFacilitator.  Instantiations of the InvariantVisitor and 
InvariantFacilitator classes encapsulate the invariants in C++ 
statements and facilitate the validation of the invariants.  We 
describe both our approach and our results of validating invariants 
in keystone, a well tested parser front-end for C++.