Standardization of program implemented with pointers and its application

In order to facilitate program analysis, a standardization method is proposed to remove variations in programs implemented with pointers. Firstly, a program is represented by a system dependence graph (SDG), and the alias information is analyzed. Then standardization rules for eliminating variations caused by pointers are proposed, and the SDG is transformed according to these rules, so that syntactically different but semantically equivalent codes can be transformed into identical SDGs. Therefore, code variations are removed. The proposed method has been applied to an automatic grading system of C programming language, and the results were compared with those of both manual and strictly precise grading systems to validate the effectiveness of our method.