Automatic Identification Of Knowlege From Program Code Based On Expert System

Personalized Online Judge system (OJ) is different with the traditional OJ, it can choose the different type of problems according to the different students with different knowledge to improve the efficiency of study for students and help them to find suitable problems more quickly.To gather statistics of students' knowledge and types of problems, the available method is to gather statistics of the codes submitted by students and the codes of problems' standard codes. But in the actual development, it's find that to collect and statistic code knowledge is a very complicated and tedious work by manual operation. The specific performance: 1) Slow and not efficiency in handling a large amount of codes. 2) Not accuracy, easy to errors or omissions when recognizing. 3) High requirements to identify person.This paper bring forth a method that automatic identify the knowledge from program code based on expert system. It will describe and the tree of knowledge points in the rule of recognition grammar induction and describe the form of an expert knowledge base, the establishment of an expert system approach to automatic recognition, statistical knowledge of the code point, the specific work is as follows: 1) Make the syntax tree by syntax analyzing. 2) Observe and analyze the form of knowledge in syntax tree and divided knowledge into fixed form and uncertain form. 3) For fixed form, using Pattern Tree to match the form, and bring forth the concept, procedures of construction and matching algorithms of Pattern Tree. 4) For uncertain form, using tree distance to calculate the similarity between the syntax trees, and makes a research of improving the accuracy of similarity. 5) Construct a grammar to depict the identification rule of knowledge by describe the Pattern Tree and the syntax tree, and record some simple and common knowledge in the expert knowledge base. 6) Accomplish a system to test and experiment.The experimental results show that the system can real-time, effectively and accurately gather the statistic of knowledge in program code and make a good prepare for the personalized OJ system.