A proposed implementation of communication primitives in Ada and CHILL for distributed systems

Call number: LD2668 .T4 CMSC 1988 U54Master of ScienceComputing and Information Science

Using signaling to aid computer program comprehension

Guidelines for using style to improve computer program comprehension have often been proposed without empirical testing. This thesis reports on the results of three controlled experiments that investigated ways program style may be used to aid comprehension of source code listings. Experiments 1 and 2 were conducted using advanced computer science students as subjects and short Pascal programs. Results showed that student programmers used meaningful identifier names as important sources of information during comprehension of short programs. A review of the literature showed the need for the thesis' proposed methodology for designing controlled experiments on program comprehension that produce results which generalize well to situations involving professional programmers working on real world tasks. This methodology was used to design Experiment 3. Text comprehension researchers have investigated the use of signaling, or the placement of non-content information, in a text in order to emphasize certain ideas and/or clarify the organization. Experiment 3 investigated the role of signaling in another domain, that of computer program source code listings. The experiment had professional programmers study a 913-line C program. Three types of signals were investigated: preview statements, headings, and typographic cueing. The major results were (a) meaningful module names served as headings in the source code listing and helped professional programmers understand and locate information in the program; (b) header comments, when written as preview statements, helped professional programmers understand and locate information in the program; (c) typographic cueing, designed to provide emphasis and segmentation cues, helped programmers understand the program; and (d) the effects of meaningful names, header comments, and typographic cueing were additive. No significant interactions of effects were observed. Based on these results, guidelines are proposed for ways programmers may use comments and module names in source code to act as signals that aid future readers. In addition, guidelines are suggested for adding typographic signaling to provide emphasis to the comments and names