. Advanced polymorphic type systems have come to play an important role in the world of functional programming. But, curiously, these type systems have so far had little impact upon widely-used imperative programming languages like C and C++. We show that ML-style polymorphism can be integrated smoothly into a dialect of C, which we call Polymorphic C. It has the same pointer operations as C, including the address-of operator &, the dereferencing operator , and pointer arithmetic. Our type...