Automatic marking of C code applied to mathematics problems
We demonstrate how we have used DEWIS to automatically assess programming skills, in particular, in the C programming language. DEWIS is fully algorithmic open-source e-Assessment system designed and developed at the University of the West of England, Bristol (UWE). It is a completely stand-alone web based system used for both summative and formative assessments. For tasks involving computer programming, students submit their computer code through DEWIS. The system performs a series of pre- and post- submission checks on the student’s code prior to compiling and executing the code on the system’s server. The student’s code may be executed a number of times against different inputs to evaluate the code’s output. This approach has been used to assess quite significant programming projects (e.g. the n-Queens problem, Dijkstra’s algorithm) as well as to support a number of ‘bite-sized’ formative assessments. We show how we are able to provide ‘intelligent feedback’ to the students’ submissions. For example, if a student’s program outputted numerical values in response to DEWIS randomly supplied inputs, the system would, in the case of incorrect answers, analyse the output for ‘common student errors’ (CSEs). The detection of such CSEs triggers an appropriate response in the feedback supplied to the student. Results show that this innovative work is making a positive impact on students.