Tree-based comparison for plagiarism detection and automatic marking of programming assignments

Sin-chun Ng, Andrew Kwok-fai Lui and Lai-shan Wong
The Open University of Hong Kong
Hong Kong SAR, China

Programming assignments are usually considered as a major assessment component of a programming course. As the number of students enrolling in programming courses has been always high, it becomes a difficult task to mark a large number of programming assignments effectively in a short period of time. Moreover, plagiarism on program codes has become a serious problem recently. Markers may not be able to locate similar scripts that they have marked before. This paper introduces an online assignment management system which allows programming assignments to be submitted online and marked effectively. The marking of programming assignments involves two processes: plagiarism detection among different submitted source codes and automatic marking of individual assignment which includes program testing on different test cases and checking across the model answer. In this paper, we propose the use of parse tree for checking the similarity between program codes. The method can be employed in plagiarism detection and automatic marking of programming assignments.