Auto-Generating Visual Exercises for Learning Program Semantics

Understanding program execution is a challenging task for novice programmers. The semantic rules which determine how execution affects the program state are numerous and complex, and students frequently hold fundamental misconceptions about these rules. If students do not build a correct mental model of program execution early on, they will face substantial hurdles as they try to develop and debug their code. This paper presents VizQuiz, a tool for auto-generating multiple choice quizzes designed to help students gain insight into the semantic rules which govern program execution. VizQuiz provides students with an initial state and a piece of code, and tasks them with mentally tracing the execution of that code and selecting the correct final state. Reference diagrams are used to depict the initial and final states, and as feedback to help students visualize the correct behavior if they select a wrong answer. Feedback is auto-generated, so students can immediately correct their misconceptions and re-attempt.