程序调试中的树形结构演变可视化模型

树形结构作为一种非线性数据结构,在程序执行过程中的演变过程较为抽象,尤其是在对其进行加工型操作时,容易发生内存泄漏。针对编程初学者难以掌握树形结构的逻辑演变过程,以及在程序中发生内存泄漏错误时调试较为困难的问题,文中提出了一种对程序调试过程中树形结构的演变过程进行可视化呈现的处理模型TEVM(Tree Evaluation Visualization Model)。针对单个可视化程序在调试步骤前和调试步骤后的两个树形结构,设计了一种将树形结构转换为线性表示的结构对比算法,得出了它们的包括泄漏树在内的结构差异;同时设计了一种树形结构布局方法,并计算它们的布局差异。根据结构差异和布局差异生成可视化演变序列,调用绘图引擎对该序列进行解析和执行,从而完成对树形结构及其演变过程的动态、平滑和直观的可视化呈现,帮助编程初学者快速理解树形结构相关程序的执行过程,提升调试效率。将TEVM模型集成于一个面向编程实训教学的集成开发环境原型Web AnyviewC中,取得了较好的应用效果。

Tree Structure Evaluation Visualization Model for Program Debugging

Tree structure is a nonlinear data structure, whose evolution process is abstract in the program execution.Memory leak happens while applying modification-like operation on it.It is an open challenge for programming beginner to control the evolution of tree structure in the program debugging procedure, especially to debug the error when memory leakage happens.To address this issue, this paper proposes a tree evaluation visualization model(TEVM) to visualize the evolution procedure of tree structure.Two tree structures are obtained after executing a visual debugging step.This paper designs a structure comparison algorithm to obtain their structural difference including leaked tree by transforming tree structure into linear representation.It also designs a tree layout method and computes their positional difference.A visual evaluation sequence is generated with these structural diffe-rence and positional difference.At last, it applys the drawing engine to interpret and execute actions of this sequence to visualize the tree structure evaluation dynamically, smoothly and intuitively.The visualization of tree structure helps programming beginner to understand the execution of program relating to tree structure and improves the efficiency of program debugging.TEVM model is applied in the Web AnyviewC,which is a prototype of the integrated development environment for programming trai-ning, and gains an excellent application effect.