Question

Problem 3:

Modify StudentLinkedList class by adding the following methods:

•  printStudentList: print by calling and printing “toString” of every object in the linkedList. Every student object to be printed in a separate line.

•  deleteStudentByID(long id): delete student object from the list whose ID is matching with the passed parameter.

•  sortListByID(): sort the linkedlist according to students IDs.

•  findMarksAverage(): find the average of all marks for all students in the list.

•  findMinMark(int markIndex): find the student with the minimum mark in a specific index:

Quizzes

Midterm Exam

Final Exam

please solve it as clear and simple as you can - java netbeans

Answer 1

import java.util.Comparator;
import java.util.LinkedList;

public class StudentLinkedList {
        
        public static void printStudentList(LinkedList<Student> ll) {
                for(int i=0; i<ll.size(); i++) {
                        System.out.println(ll.get(i));
                }
                System.out.println();
        }
        
        public static void deleteStudentByID(LinkedList<Student> ll, long id) {
                for(int i=0; i<ll.size(); i++) {
                        if(ll.get(i).getID() == id) {
                                ll.remove(i);
                                System.out.println("Deleted successfully.");
                                return;
                        }
                }
                
                System.out.println("Unable to find the student with id " + id);
        }
        
        public static void sortListByID(LinkedList<Student> ll) {
                ll.sort(new Comparator<Student>() {

                        @Override
                        public int compare(Student o1, Student o2) {
                                return (int) (o1.getID() - o2.getID());
                        }
                });
        }
        
        public static double findMarksAverage(LinkedList<Student> ll) {
                double totalMarks = 0;
                for(int i=0; i<ll.size(); i++) {
                        int marks[] = ll.get(i).getMarks();
                        totalMarks += marks[0] + marks[1] + marks[2];
                }
                return totalMarks/ll.size();
        }
        
        public static double findMinMark(LinkedList<Student> ll, int markIndex) {
                int minMark = 100;

                for(int i=0; i<ll.size(); i++) {
                        int marks[] = ll.get(i).getMarks();
                        
                        if(marks[markIndex] < minMark) {
                                minMark = markIndex;
                                minMark = marks[markIndex];
                        }
                }
                
                return minMark;
        }
        
        public static void main(String[] args) {
                LinkedList<Student> linkedlist = new LinkedList<>();
                linkedlist.add(new Student("Ahmed Ali", 20111021, 18, 38, 38));
                linkedlist.add(new Student("Sami Kamal", 20121021, 17, 39, 35));
                linkedlist.add(new Student("Salem Salim", 20131021, 20, 40, 40));
                linkedlist.add(new Student("Rami Mohammed", 20111031, 15, 35, 30));
                linkedlist.add(new Student("Kim Joe", 20121024, 12, 32, 32));
                linkedlist.addFirst(new Student("Hadi Ali", 20111025, 19, 38, 39));
                linkedlist.addLast(new Student("Waleed Salim", 20131025, 10, 30, 30));
                linkedlist.set(0, new Student("Khalid Ali", 20111027, 15, 30, 30));
                linkedlist.removeFirst();
                linkedlist.removeLast();
                linkedlist.add(0, new Student("John Don", 20131025, 11, 31, 31));
                linkedlist.remove(2);
                
                printStudentList(linkedlist);
                deleteStudentByID(linkedlist, 20121024);
                printStudentList(linkedlist);
                
                sortListByID(linkedlist);
                printStudentList(linkedlist);
                
                System.out.println("Average marks by all: " + findMarksAverage(linkedlist));
                System.out.println("Min Quizzes marks by student: " + findMinMark(linkedlist, 0));
                System.out.println("Min Midterm marks by student: " + findMinMark(linkedlist, 0));
                System.out.println("Min Final exam marks by student: " + findMinMark(linkedlist, 0));
        }
}

class Student {
        private String name;
        private Long ID;
        private int[] marks = new int[3];

        public Student(String name, long ID, int quizzes, int mid, int fin) {
                this.name = name;
                this.ID = ID;
                marks[0] = quizzes;
                marks[1] = mid;
                marks[2] = fin;
        }

        public String getName() {
                return name;
        }

        public Long getID() {
                return ID;
        }

        public int[] getMarks() {
                return marks;
        }

        @Override
        public String toString() {
                String temp = "student: " + "name = " + name + ", ID = " + ID + ", marks = {" + marks[0] + ", " + marks[1]
                                + ", " + marks[2] + "}";
                return temp;
        }
}

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