Power law distribution of R\'enyi entropy for equilibrium systems having nonadditive energy

Using R'enyi entropy, a possible thermostatistics for nonextensive systems is discussed. We show that it is possible to get the $q$-exponential distribution function for nonextensive systems having nonadditive energy but additive entropy. It is also shown that additive energy, as a approximation within nonextensive statistics, is not suitable for discussing fundamental problems for interacting systems.