We introduce an imperative programming language called QPT (Quantum Poly-Time) with recursion rules that captures the complexity class FBQP (Functions Bounded-error Quantum Polytime), the class of functions computable in polynomial time by a quantum Turing machine with at most 1/3 probability of error, commonly accepted as the class of feasible problems for quantum computers. Our result takes advantage of a function algebra proposed by Yamakami characterizing FBQP.