CMBEASY: an object oriented code for the cosmic microwave background

We have ported the CMBFAST package to the C++ programming language to produce CMBEASY, an object oriented code for the cosmic microwave background. The code is available at www.cmbeasy.org. We sketch the design of the new code, emphasizing the benefits of object orientation in cosmology, which allow for simple substitution of different cosmological models and gauges. Both gauge-invariant perturbations and quintessence support has been added to the code. For ease of use, as well as for instruction, a graphical user interface is available.