A visual programming environment for data-structured programming

Typescript (photocopy).This research involved the design and development of the Visual Programming Environment for a Limited Abstract Data Type Set (VPE-LADTS), a graphical software development tool for use in the creation of data-structured programs. The primary motivation for the research was twofold: 1) to investigate the potential application of data-structured programming in the educational and professional arenas, and 2) to provide an environment immediately usable to enhance introductory education in the use of data-structured programming and abstract data types. Data-structured programming (DSP), which uses a limited set of abstract data types in place of arrays and pointers, has recently been advanced in the literature as a programming methodology which results in programs that are shorter, simpler, and easier to understand than array-based programs. Visual Programming addresses methods of increasing a program's comprehensibility through the display and modification of software using visual and graphical means. Using a new category of visual programming language (the icon-based visual programming language), the VPE-LADTS features a combined text and graphic presentation of a data-structured program, and permits the use of dynamic data-structure and control-flow visualization, along with software engineering methods such as top-down design with step-wise refinement, procedural abstraction, and incremental development of algorithms. The results of a formative evaluation of both data-structured programming and the VPE-LADTS are presented. With regard to DSP, the results suggest that data-structured programming is a promising methodology and that further research is indicated to identify both the application areas DSP is suited for and the particular abstract data types needed for those areas. Experiences with the VPE-LADTS indicate that the environment can be used to effectively enhance introductory computer science education through a tight integration of visual programming and data-structured programming techniques, and that the VPE-LADTS provides a usable tool for a group that traditionally has not been provided with many software tools