Teaching object-orientation with smartphones as digital CRC cards

Object-orientation is one of the essential parts of every software engineering course. However, according to literature, it often lacks the following: First, modeling on a conceptual level independent from a particular programming language is often neglected. Moreover, the actual process of designing or implementing a piece of software seems to be less important than providing an optimal solution. Finally, students often follow the slides of the teacher passively without thinking about or even questioning the material. But, in order to actively apply a proper form of object-orientation, it is essential that one understands the concepts of this programming paradigm and is able to deal with problems and communicate ideas rather than handling a specific programming language. In this paper we introduce CREWSpace-a tool for co-located collaboration that implements a digital version of the CRC method. To this end, students actively participate in so called CRC sessions, which fosters communication and problem solving skills. In particular, they design a software system on a conceptual level and use our tool to analyze and adjust the proposed design through role play. Moreover, CREWSpace records these analyses for a later replay such that the students are able to reflect on their decisions.