Cornelia M. Yoder, Marilyn L. Schrag • 2025/03/26
Software Engineering
The paper "Nassi-Shneiderman Charts: An Alternative to Flowcharts for Design" by Cornelia M. Yoder and Marilyn L. Schrag discusses the use of Nassi-Shneiderman (N-S) charts as a tool for structured programming. Published in 1978, it highlights how these charts, developed by I. Nassi and B. Shneiderman in 1972, serve as an effective alternative to traditional flowcharts during both the design and coding phases of program development. The authors, working at IBM’s System Products Division in Endicott, New York, explain that N-S charts have been adopted by several programming groups as a replacement for conventional flowcharts. These charts are particularly valuable in structured programming—a methodology focused on improving program correctness, maintainability, modifiability, and readability—over older priorities like efficiency and creative obscurity. The paper outlines how N-S charts align with structured programming by enforcing a disciplined, modular design approach that avoids unstructured elements like arbitrary control transfers.
The paper provides a detailed description of N-S chart symbols, such as PROCESS, IFTHENELSE, DOWHILE, DOUNTIL, and CASE structures, and illustrates their use with examples like an FICA deduction report. It emphasizes practical applications, including creating logic designs, coding, testing, and documentation. N-S charts are praised for their clarity, ability to fit on a single page, and ease of translation into structured code, making them useful for walkthroughs, design reviews, and programmer education. The authors also compare N-S charts to other methods like pseudo-code, HIPO charts, prose, and traditional flowcharts, noting that each has strengths depending on the context. For instance, N-S charts excel in detailed logic design and visual representation, while pseudo-code is better for inline documentation, and HIPO charts suit high-level functional overviews. The paper concludes that N-S charts are a versatile, elegant tool that supports structured programming goals and have potential for broader application beyond programming, such as in procedural documentation or other technical fields.
I found this paper intriguing because it presents a simple and concise way to visualize the efficiency and logic of programs, which feels like a refreshing shift from the often cluttered traditional flowcharts. The structured nature of N-S charts really appeals to me—it’s like they force you to think clearly and logically from the start. I’m excited to try incorporating them into my own projects, though I can’t help but wonder if they’d hold up as well with more complicated systems where logic might sprawl beyond a single page. Still, their elegance and practicality make them stand out, and I highly recommend reading the paper to see how they work in action!