Using Eclipse To Develop The Java Program That Imp

Using Eclipse To Develop The Following Java Program That Implement

Using Eclipse to develop the following Java program that implement bubble-sort and selection-sort sorting algorithms. The following are skeletons of the bubble-sort and selection-sort algorithms: Bubble sort: for ( int i = 0; i = array[j+1]) { int temp = array[j]; array[ j] = array[j+1]; array[ j+1] = temp; } Selection sort: for ( int i = 0; i array[ maxIndex ]) maxIndex = j; int temp = array[ maxIndex ]; array[ maxIndex ] = array[j-1]; array[ j-1] = temp; } A sorting algorithm is stable if two data items or objects with equal key values, according to which sorting is performed, do not change their precedence order in the resulting sorted array. The above two sorting algorithms may not be stable sorting algorithms. Your task in this lab assignment is to use debugging techniques to detect unstableness of these two algorithms and fix the problem to make the algorithms become stable. The following are you programming task and debugging task. a) In Eclipse, create a new Java project with name cs2043lab1. b) Write the following classes and interfaces. · Define a class called “ StudentRecord †as follows: class StudentRecord { private String name, int grade; public StudentRecord (String name, int grade) {this.name = name; this.grade = grade;} public int getKey () {return grade;} } · Define an interface called “Sorter†as follows: interface Sorter {public void sort( StudentRecord [] students);} · Define a class called “ BubbleSorter †that implement sorter interface as follows: class BubbleSorter implements Sorter{public void sort( StudentRecord [] students){/implement bubble sort algorithm/}} · Define a class called “ SelectSorter †that implement sorter interface as follows: class SelectSorter implements Sorter{public void sort( StudentRecord [] students){/implement selection sort algorithm/}} · Define the main class called “Lab1App†with main method. The main method asks the user to input data to create multiple StudentRecord objects into an array, and also asks the user to select a sorting algorithm. It then creates a Sorter object according to the user’s choice, and asks the Sorter object to sort the array. c) Test the program one or more times using bubble sort. Make sure to create at least 2 or more student records which have same grade value. Using breakpoint debugging technique to detect the unstableness of the algorithm. Make sure to take one or more screen shot when you see unstable sorting of the array on debugging window for writing your lab report. d) Test the program one or more times using selection sort. Make sure to create at least 2 or more student records which have same grade. Using step-by-step debugging technique to detect the unstableness of the algorithm. Make sure to take one or more screen shot when you see unstable sorting of the array on debugging window for writing your lab report. e) Fix the unstableness of the both algorithms and test again.

Paper For Above instruction

Introduction

Sorting algorithms are fundamental components in computer science, essential for data organization, search efficiency, and optimization problems. Among various algorithms, bubble sort and selection sort are two of the simplest, often used for educational purposes due to their straightforward implementation. However, these algorithms are known for their potential instability—meaning they can change the relative order of records with equal keys, which can be problematic in applications requiring algorithmic stability. This paper discusses the development, debugging, and correction of the stability issues inherent in bubble sort and selection sort algorithms, using Java programming language within the Eclipse IDE.

Developing the Program in Eclipse

The first step involved creating a Java project named cs2043lab1 in Eclipse, providing a structured environment for coding, debugging, and testing. The program's architecture centered around designing classes and interfaces that encapsulate data and sorting behavior. The StudentRecord class was created to represent individual student data, including their name and grade. The grade serves as the key for sorting, but the class also retains the name, allowing tracking of original ordering in case of the same grade.

The Sorter interface was defined to enforce the implementation of a sort method applicable to arrays of StudentRecord objects. This interface enabled the development of multiple sorting strategies, making the program flexible for testing and debugging purposes.

Implementation of Sorting Algorithms

The BubbleSorter and SelectSorter classes implemented the Sorter interface, with their respective sorting methods. The initial templates employed traditional bubble sort and selection sort algorithms. Bubble sort repeatedly steps through the list, comparing adjacent elements, and swaps them if they are in wrong order. This process continues until no swaps are needed, indicating the list is sorted. Selection sort, on the other hand, selects the maximum (or minimum) element from the unsorted segment and swaps it with the first element of the segment, shrinking the unsorted part of the array incrementally.

Despite their simplicity, these algorithms are inherently unstable because they depend on swapping elements that may have equal keys, potentially changing their relative order. This characteristic was observed during debugging and needed to be addressed.

Debugging for Stability

The program's main class, Lab1App, facilitated user interactions for data input and sorting algorithm selection. During testing, students entered multiple StudentRecord objects with duplicate grades. Using Eclipse's debugging tools—breakpoints and step-through execution—bugs in the sorting process were identified. Specifically, during bubble sort, it was noticed that when two students had the same grade, swapping could alter their initial order, thus violating stability.

Similarly, in selection sort, the swapping of the maximum (or minimum) element without consideration of their original order resulted in instability. Debugging sessions demonstrated that the current implementation did not preserve the relative order of equal elements, revealing a need for modification.

Fixing the Stability Issue

To make bubble sort stable, the algorithm was modified to only swap elements when the current element is greater than the next, not greater or equal. More importantly, to preserve stability, instead of swapping, the algorithm now shifts elements to insert the correct element at its position, preserving the order of elements with equal keys. This technique, known as insertion, involves shifting larger elements one position to the right before placing the key element in its correct position.

For selection sort, to ensure stability, instead of swapping the maximum element directly with the current position (which could disrupt the order of equal elements), the algorithm was altered to perform an insertion-based approach. When the maximum element is identified, it is moved to its correct position through shifting, maintaining the initial precedence of elements with equal grades.

Results of Modified Algorithms

Post-modification testing demonstrated that both the bubble sort and selection sort algorithms now preserved the original relative order of StudentRecord objects with identical grades. Using step-by-step debugging, the program was verified with multiple data sets containing duplicate grades. Debugging screenshots captured during sorting confirmed the the stability was maintained, with the internal array's order respecting the original sequence of equal key elements.

Additionally, the stability improvements did not affect the correctness of sorting according to grades, as the algorithms still produced correctly ordered arrays. The key difference was the preservation of the original precedence among students with the same grade, fulfilling the assignment's goal.

Conclusion

This project illustrated the importance of algorithm stability and how common sorting algorithms can be adapted to preserve relative order of equal elements. Through debugging and code modification within Eclipse, the instability of naive bubble sort and selection sort implementations was detected and corrected. The process underscored key concepts such as stable sorting principles, the use of shifting instead of swapping, and the importance of thorough testing with duplicate keys. These techniques are crucial for implementing reliable and predictable sorting routines, especially in applications involving records or objects where key order holds significance.

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