skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Evaluating How Novices Utilize Debuggers and Code Execution to Understand Code
Background: Previous work has shown that students can understand more complicated pieces of code through the use of common software development tools (code execution, debuggers) than they can without them. Objectives: Given that tools can enable novice programmers to understand more complex code, we believe that students should be explicitly taught to do so, to facilitate their plan acquisition and development as independent programmers. In order to do so, this paper seeks to understand: (1) the relative utility of these tools, (2) the thought process students use to choose a tool, and (3) the degree to which students can choose an appropriate tool to understand a given piece of code. Method: We used a mixed-methods approach. To explore the relative effectiveness of the tools, we used a randomized control trial study (š‘ = 421) to observe student performance with each tool in understanding a range of different code snippets. To explore tool selection, we used a series of think-aloud interviews (š‘ = 18) where students were presented with a range of code snippets to understand and were allowed to choose which tool they wanted to use. Findings: Overall, novices were more often successful comprehending code when provided with access to code execution, perhaps because it was easier to test a larger set of inputs than the debugger. As code complexity increased (as indicated by cyclomatic complexity), students become more successful with the debugger. We found that novices preferred code execution for simpler or familiar code, to quickly verify their understanding and used the debugger on more complex or unfamiliar code or when they were confused about a small subset of the code. High-performing novices were adept at switching between tools, alternating from a detail-oriented to a broader perspective of the code and vice versa, when necessary. Novices who were unsuccessful tended to be overconfident in their incorrect understanding or did not display a willingness to double check their answers using a debugger. Implications: We can likely teach novices to independently understand code they do not recognize by utilizing code execution and debuggers. Instructors should teach students to recognize when code is complex (e.g., large number of nested loops present), and to carefully step through these loops using debuggers. We should additionally teach students to be cautious to double check their understanding of the code and to self-assess whether they are familiar with the code. They can also be encouraged to strategically switch between execution and debuggers to manage cognitive load, thus maximizing their problem-solving capabilities.  more » « less
Award ID(s):
2121424
PAR ID:
10644126
Author(s) / Creator(s):
; ;
Publisher / Repository:
ACM
Date Published:
Page Range / eLocation ID:
65 to 83
Subject(s) / Keyword(s):
code comprehension debuggers execution
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. When learning to code a student must learn both to create a program and then how to debug said program. Novices often start with print statements to help trace code execution and isolate logical errors. Eventually, they adopt advance debugger practices such as breakpoints, "stepping" through code execution, and "watching" variables as their values are updated. Unfortunately for students working with Arduino devices, there are no debugger tools built into the Arduino IDE. Instead, a student would have to move onto a professional IDE like Atmel Studio and/or acquire a hardware debugger. Except, these options have a steep learning curve and are not intended for a student who has just started to learn how to write code. I am developing an Arduino software library, called Pin Status, to assist novice programmers with debugging common logic errors and provide features specific to the e-textile microcontroller, Adafruit Circuit Playground Classic. 
    more » « less
  2. Explain in Plain English (EiPE) questions evaluate whether students can understand and explain the high-level purpose of code. We conducted a qualitative think-aloud study of introductory programming students solving EiPE questions. In this paper, we focus on how students use tracing (mental execution) to understand code in order to explain it. We found that, in some cases, tracing can be an effective strategy for novices to understand and explain code. Furthermore, we observed three problems that prevented tracing from being helpful, which are 1) not employing tracing when it could be helpful (some struggling students explained correctly after the interviewer suggested tracing the code), 2) tracing incorrectly due to misunderstandings of the programming language, and 3) tracing with a set of inputs that did not sufficiently expose the code’s behavior (upon interviewer suggesting inputs, students explained correctly). These results suggest that we should teach students to use tracing as a method for understanding code and teach them how to select appropriate inputs to trace. 
    more » « less
  3. null (Ed.)
    Open-ended programming increases students' motivation by allowing them to solve authentic problems and connect programming to their own interests. However, such open-ended projects are also challenging, as they often encourage students to explore new programming features and attempt tasks that they have not learned before. Code examples are effective learning materials for students and are well-suited to supporting open-ended programming. However, there is little work to understand how novices learn with examples during open-ended programming, and few real-world deployments of such tools. In this paper, we explore novices' learning barriers when interacting with code examples during open-ended programming. We deployed Example Helper, a tool that offers galleries of code examples to search and use, with 44 novice students in an introductory programming classroom, working on an open-ended project in Snap. We found three high-level barriers that novices encountered when using examples: decision, search, and integration barriers. We discuss how these barriers arise and design opportunities to address them. 
    more » « less
  4. Abstract Source code is a form of human communication, albeit one where the information shared between the programmers reading and writing the code is constrained by the requirement that the code executes correctly. Programming languages are more syntactically constrained than natural languages, but they are also very expressive, allowing a great many different ways to express even very simple computations. Still, code written by developers is highly predictable, and many programming tools have taken advantage of this phenomenon, relying on language modelsurprisalas a guiding mechanism. While surprisal has been validated as a measure of cognitive load in natural language, its relation to human cognitive processes in code is still poorly understood. In this paper, we explore the relationship between surprisal and programmer preference at a small granularity—do programmers prefer more predictable expressions in code? Usingmeaning‐preserving transformations, we produce equivalent alternatives to developer‐written code expressions and run a corpus study on Java and Python projects. In general, language models rate the code expressions developerschooseto write as more predictable than these transformed alternatives. Then, we perform two human subject studies asking participants to choose between two equivalent snippets of Java code with different surprisal scores (one original and transformed). We find that programmersdoprefer more predictable variants, and that stronger language models like the transformer align more often and more consistently with these preferences. 
    more » « less
  5. Recent advances in Large Language Models (LLM) have made automatic code generation possible for real-world programming tasks in general-purpose programming languages such as Python. However, there are few human studies on the usability of these tools and how they fit the programming workflow. In this work, we conducted a within-subjects user study with 24 participants to understand how programmers use and perceive Copilot, a LLM-based code generation tool. We found that, while Copilot did not necessarily improve the task completion time or success rate, most participants preferred to use Copilot in daily programming tasks, since Copilot often provided a useful starting point and saved the effort of searching online. However, participants did face difficulties in understanding, editing, and debugging code snippets generated by Copilot, which significantly hindered their task-solving effectiveness. Finally, we highlighted several promising directions for improving the design of Copilot based on our observations and participants’ feedback. 
    more » « less