NPDA: A Teaching Tool on Nondeterministic Pushdown Automata

Abstract

Automata and Language Theory is a difficult subject in a computer science curriculum. One of the concepts that are difficult to understand in this subject area is the concept of a Pushdown Automata (PDA). The system was developed to provide the user with a simulation and a tutorial on the said topic. The tool would show a step-by-step process how a string is accepted by a PDA. An input grammar from the user is converted to its equivalent PDA. The Cocke-Younger-Kasami (CYK) algorithm was used to check if an input string is accepted. The system simulates how the stack is used by the machine in processing the user input. The tutorial part provides online lectures and quizzes for the user to understand the topics more effectively.