Research And Realization For Program Assessment Automatically

Computer Auxiliary Assessment(CAA) has got more attention in the recent years. Objective problems being resolved, there are not any good methods appeared for subjective problems because of their variety and creativity. Student program exercises belong to subject problems. Since program language has some features different from human language, such as strongly rigid criterion, fewer multivocal situations, and here mainly moderate size programs processed.CAA for student program is studied in this paper. On the basis of program studying visualization environment, which was developed by our studio, student program is assessed logically using automated program assessment technique based on model programs. That would benefit not only beginner from comprehension and mastery of basic program concepts and design methods, but also tutors from original tasks alleviation, and in the mean time, program assessment work would be more impersonal, exact, and real-time.The goal is to design and to implement the program assessment system. In the system, the idea of comparing source codes' features is adopted. Student program and model programs stored in the problem library are compared in turn, and then assessment result about accomplished degree and quality of student program is acquired through assessment rules based on the concept of Equivalent Degree. Before comparing student program with model program, a series of work is needed to be done, such as information abstraction, structure transformation. After source program inputted, information tree of program control structure, which is called extended syntax tree (EST) , is produced by syntax analyzing process; Extended flow graph (EFG) is produced by data flow analyzing on the basis of EST; Program Features and Attributes graph (PFSG) is produced on the basis of EFG by a series of techniques, such as program basic block partition, control dependence and data...