-void zipf_init(struct zipf_state *zs, unsigned long nranges, double theta, unsigned int seed);
-unsigned long long zipf_next(struct zipf_state *zs);
+void zipf_init(struct zipf_state *zs, uint64_t nranges, double theta, unsigned int seed);
+uint64_t zipf_next(struct zipf_state *zs);