Algorithms and data structures: Dynamic visualization of operation in a programming environment for educational purposes

Abstract

Data structures and the algorithms that manipulate and transform these data to solve problems are a fundamental subject in computer science, with wide-ranging applications in many different fields and classes of problems. Despite the fundamental role that algorithms play in computer science, students often struggle to understand this subject. There are several reasons why students struggle, including fear of programming (especially for those with no prior programming experience), lack of interest, and the abstract nature of the concepts involved, such as the concept of the complexity of an algorithm. These are the main causes of high drop-out and failure rates in core compulsory courses of the curriculum, such as courses in programming, data structures and complex algorithms. A related subject that is considered both difficult and important is the analysis and design of algorithms. To address this problem, many research studies have been conducted on how to improve the teaching and learning process of algorithms. As the volume of information increases rapidly, so does the need to sort data for better analysis and study, which gives increasing importance to sorting algorithms. These algorithms are also the main focus of this thesis. Sorting is a need that arises in the physical world, to facilitate the search for a specific entity within a large volume of data. Since ancient times, people have developed indexes, dictionaries, directories, and other forms to keep useful information organized, especially if the data set is dynamic, meaning if new data is constantly being generated while old data must be removed or deleted. Many and quite different sorting algorithms have been developed to improve performance in terms of computational complexity and ultimately the resources (time and space) required, depending on the size of the data. In comparative assessment between alternative algorithms, there are several factors to consider, such as the time complexity, the (extra) memory space that will be required, and the stability of each algorithm. Returning to the educational problem of optimal teaching and learning of the subject for today's students, based on research, Algorithm Visualization has been shown to have a positive impact on student learning. This thesis aims to design and develop a graphical tool for visualizing sorting algorithms that can be easily used by students. Visualization emphasizes the visual representation of steps and operations of an algorithm and is generally considered more effective than verbal or numerical presentations of the subject in terms of understanding and being a user-friendly process. Interactive visualization tools available today can be used effectively to teach and learn complex concepts. In particular, in the subject matter, graphically illustrating the steps and operations of algorithms, dynamically while they are running, can help students understand and compare different classification algorithms more effectively. The purpose of this thesis is, in the first place, to make a brief reference to the subject of algorithms and their different types, in order to understand their importance. Also, before designing the application, a brief reference will be made to the basic issues of the complexity of the algorithms. Complexity is used as a tool to measure the effectiveness of an algorithm, as it is fundamental to understanding the different requirements and performances between sorting algorithms. Based on this knowledge, the following sorting algorithms will then be presented: • Bubble Sort, • Selection Sort, • Insertion Sort, • Merge Sort, and • Quick Sort. This will help the reader and ultimately the student to gain a basic level of understanding of these methods, as a necessary basis for fully understanding them with the help of the visualization tool. Finally, an online, web-based application will be designed and implemented in which the user will be able, among other functions, to enter or select a sequence of positive integer input numbers and select a specific one of the 5 available sorting algorithms. By using a bar graph based visualization tool, the student will gain a better understanding of how the particular algorithm works. In addition, the student will be able to run it on its own data, or use the same "random" data to compare two or more algorithms. The design has emphasized functionality from an educational/teaching point of view, as the primary role of the application is to be a support tool for the teacher in a university department.