1,720,975 research outputs found
Comparing Small Programs for Equivalence: A Code Comprehension Task for Novice Programmers
Full text linkNovice programmers should develop program comprehension skills as they learn to code so that they are able both to read and reason about code created by others, and to reflect on their code when writing, debugging or extending it. This work takes a little-explored perspective on the comprehension of small programs by asking students to decide if two code segments are equivalent or not in terms of carrying out the same computation. A variation of Euclid's algorithm, that extends the greatest common divisor calculation to more than two numbers, was chosen for this work, as it has an adequate level of complexity and its semantics are not obvious. Four program transformations of the original code were developed: two transformations were equivalent and two were not. 73.5% of students were able to identify correctly the four options and 75.5% provided good insights on the equivalent program flow to justify their choices. The overall task has a SOLO mean of 3.19, which indicates code equivalence is a suitable and approachable task to analyse program execution at novice level. In addition, the data analysis suggests that students' code-reading abilities beyond basic tracing may be generally underestimated and we should investigate how to bridge the potential gap between reasoning about program execution and extracting its purpose
Learning Transfer in Novice Programmers: A Preliminary Study
Full text linkLearning transfer refers to the ability to correctly apply learned skills, knowledge and behaviors to new situations or contexts. This paper explores novice programmers' transfer through the analysis of two related coding tasks completed by CS1 students as part of their assessment. The first task was a take-home practical and the second task was a lab practical exam; both tasks requested the implementation of a C function with an integer parameter from which the digits are to be extracted and operated on. The solution set generated from each task by a cohort of 255 CS1 students has been explored and classified in order to determine the extent of transfer from the practice task to the later assessment task. This classification shows 36.5% of students consolidated or extended the acquired skills and 13% at least partly; 38%, on the other hand, failed to recall their previous valid strategy or to devise a better one, and were unsuccessful in the second task. On the positive side, 9% of students devised a different and improved strategy in the exam, indicating additional learning had occurred in between the two tasks. Peer review of key coding tasks could improve transfer by forcing weaker students to compare and evaluate different design strategies
Asking Students to Refactor their Code: A Simple and Valuable Exercise
No full textWhilst most undergraduate students eventually produce functionally correct code, they often disregard their code style and overall quality when it is not graded. As reported by the literature, quality defects affect both code structure and code style, and these issues seem to persist even in later years. This paper reports on the potential of a low-cost intervention that directed CS2 students to revise and refactor their code, with a specific focus on code structure, by resorting to a range of online refactoring resources. A "refactor-your-working-solution'' assignment received 73 submissions by 47 students. For each cleaned solution, students were required to provide a one-page report documenting their improvements step-by-step, and include a short reflection on their learning. Their efforts to clean code and their reflections are analysed in this experience report. Most students were able to apply multiple refactoring steps as well as other editing steps to improve their code style. In particular, we have identified a wide range of code smells in their code, hence gaining insights on their success in locating and removing 90% of them. Additionally, students' reflections appear to indicate an increased awareness as to the importance of readability and the need to develop more consistent habits when planning, coding and documenting their software
Towards Comprehensive Assessment of Code Quality at CS1-Level: Tools, Rubrics and Refactoring Rules
No full textWhile most student code is assessed for correctness and functionality, recent work has looked at extending automatic assessment to include quality aspects. In software engineering code reviews help developers to increase the quality of a project by identifying and cleaning poor structures — commonly referred to as code smells. Despite the availability of professional tools, evaluating the quality of small programs at CS1 level is quite different from evaluating a complex software system. Thus, identifying meaningful quality criteria for small programs written by novices and either adapting current tools or designing new ones for that purpose are topics worth being investigated. The present work contributes to this aim by analysing the code produced by CS1 students from three different perspectives: (i) inspecting the feedback of automated tools — Hyperstyle and Pylint; (ii) matching the smells addressed by a set of refactoring rules; (iii) devising and using a manual rubric. A comparative analysis indeed highlights strengths and weaknesses of these approaches. Overall, automatic quality feedback needs to be complemented with classroom instruction to manually detect code issues and decide if they need refactoring. Additionally, such review activities have the potential to develop code comprehension by engaging novice programmers to reflect on their own code.Cruz Izu, Claudio Mirol
High-school students' mastery of basic flow-control constructs through the lens of reversibility
Full text linkHigh-school students specialising in computing fields need to develop the abstraction skills required to understand and create programs. Novices' difficulties at high-school level, ranging from mastery of the "notional machine"to recognition of a program's purpose, have not been investigated as extensively as at tertiary level. This work explores high-school students' code comprehension by asking to reason about reversing conditional and iteration constructs. A sample of 205 K11 - 13 students from different institutions were asked to engage in a set of "reversibility tasklets". For each code fragment, they need to identify if its computation is reversible and either provide the code to reverse or an example of a value that cannot be reversed. For 4 such items, after extracting the recurrent patterns in students' answers, we have carried out an analysis within the framework of the SOLO taxonomy. Overall, 74% of answers correctly identified if the code was reversible but only 42% could provide the full explanation/code. The rate of relational answers varies from 51% down to 21%, the poorest performance arising for a small array-processing loop (and although 65% of the subjects had correctly identified the loop as reversible). The instruction level did not have a strong impact on performance, indicating such tasks are suitable for K11, when the basic flow-control constructs are usually introduced. In particular, the reversibility concept could be a useful pedagogical instrument both to assess and to help develop students' program comprehension
Exploring CS1 Student's Notions of Code Quality
No full textCoding tasks combined with other activities such as Explain in Plain English or Parson Puzzles help CS1 students to develop core programming skills. Students usually receive feedback of code correctness but limited or no feedback on their code quality. Teaching students to evaluate and improve the quality of their code once it is functionally correct should be included in the curricula towards the end of CS1 or during CS2. However, little is known about the student's perceptions of code quality at the end of a CS1 course. This study aims to capture their developing notions of code quality, in order to tailor class activities to support code quality improvements. We directed students to think about the overall quality of small programs by asking them to rank a small set of solutions for a simple problem solving task. Their rankings and explanations have been analysed to identify the criteria underlying their quality assessments. The top quality criteria were Performance (64%), Structure (51%), Conciseness (42%) and Comprehensibility (42%). Although fast execution is a key criteria for ranking, their explanations on why a given option was fast were often flawed, indicating students need more support both to evaluate performance and to include readability or comprehensibility criteria in their assessment
Abstraction in Computer Science Education: An Overview
Full text linkWhen we “think like a computer scientist,” we are able to systematically solve problems in different fields, create software applications that support various needs, and design artefacts that model complex systems. Abstraction is a soft skill embedded in all those endeavours, being a main cornerstone of computational thinking. Our overview of abstraction is intended to be not so much systematic as thought provoking, inviting the reader to (re)think abstraction from different – and perhaps unusual – perspectives. After presenting a range of its characterisations, we will explore abstraction from a cognitive point of view. Then we will discuss the role of abstraction in a range of computer science areas, including whether and how abstraction is taught. Although it is impossible to capture the essence of abstraction in one sentence, one section or a single paper, we hope our insights into abstraction may help computer science educators to better understand, model and even dare to teach abstraction skills
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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