Program Visualization systems use graphics and animation to represent the behavior of software programs. These systems represent different aspects of the program such as source code, control flow, data structures, runtime state of the program. Representing the actual runtime state of the program finds its use in a variety of applications including program understanding, visual debugging, and pedagogy. However, existing state-of-the-art program visualization systems are limited in : (1) not providing sufficient interactive capabilities to the user; (2) not faithfully representing the runtime state of the program; (3) not allowing users to apply different layout strategies to the visualization; (4) being tied to a specific programming language. To address these limitations, this thesis presents HDPV, a program state visualization system that visualizes any C, C++, or Java program. HDPV is based on a canonical state model that represents the memory layout of the program as a graph of memory blocks. It decouples the visualization of the program from the actual programming language in which it is written, thereby making the system language independent. HDPV supports a host of interactive features that allow the user to selectively explore different parts of the program's runtime state. Novel layout strategies support customization through user interaction. We provide a list of use-cases to show that HDPV can be applied to a wide variety of applications including - but not limited to - understanding programs that use basic concepts in computer science, demonstrating algorithm implementations, and debugging software programs. / Master of Science

In the arena of software development, implementing a software design (no matter how perfect the design) is rarely done right the first time. Consequently, debugging one's own (or someone else's) software is inevitable, and tools that assist in this often-arduous task become very important with respect to reducing the cost of debugging as well as the cost of the software life cycle as a whole. Many tools exist with this aim, but all are lacking in a key area: information visualization. Applying information visualization techniques such as zooming, focus and context, or graphical representation of numeric data may enhance the visual debugging experience. To this end, drawing data structures as graphs is potentially a step in the right direction, but more must be done to maximize the value of time spent debugging and to minimize the actual amount of time spent debugging. This thesis will address some information visualization techniques that may be helpful in debugging (specifically with respect to visual debugging) and will present the results of a small pilot study intended to illustrate the potential value of such techniques. / Master of Science