In Course class, add a linked list as array of nodes for grade (refer to Section 7.4 and ch07.array.ArrayRefSortedStringList). Similar to ch07.array.ArrayRefSortedStringList class, you will need an ArrayRefSortedIntList to store integer-type grade information (instead of String) and a refer to student object. Feel free to reuse ArrayRefSortedStringList, customize it for your purpose and integrate your implementation into the Course class (you will need to implement those methods that are not implemented in the ArrayRefSortedStringList class). Again, the list is a sorted list according to the grade.

Included below I have the ArrayRefSortedStringList class, and the Course class. All that is needed is for the last 4 methods of Course to be implemented. Thank you in advance.

Here is the ArrayRefSortedStringList class:

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package ch07.array;

import ch06.lists.*;

public class ArrayRefSortedStringList implements ListInterface { protected static final int NUL = -1; // End of list symbol

protected class AListNode { private String info; // The info in a list node private int next; // A link to the next node on the list }

protected AListNode[] nodes; // Array of AListNode holds the linked list

protected int list; // Reference to the first node on the list protected int free; // Reference to the first node on the free list

protected int numElements; // Number of elements in the list protected int currentPos; // Current position for iteration

// set by find method protected boolean found; // true if element found, else false protected int location; // node containing element, if found protected int previous; // node preceding location

public ArrayRefSortedStringList(int maxElements) // Instantiates and returns a reference to an empty list object with // room for maxElements elements { nodes = new AListNode[maxElements]; for (int index = 0; index < maxElements; index++) nodes[index] = new AListNode();

// Link together the free nodes. for (int index = 1; index < maxElements; index++) nodes[index - 1].next = index; nodes[maxElements - 1].next = NUL;

list = NUL; free = 0; numElements = 0; currentPos = NUL; }

protected int getNode() // Returns the index of the next available node from the free list // and updates the free list index { int hold; hold = free; free = nodes[free].next; return hold; }

protected void freeNode(int index) // Frees the node at array position index by linking it into the // free list { nodes[index].next = free; free = index; }

public boolean isFull() // Determines whether this list is full { return (free == NUL); }

private void find(String element) { found = false; int current = list; previous = NUL; while (!found && current != NUL ) { if(nodes[current].info.equalsIgnoreCase(element)) { found = true; location = current; return; } previous = current; current = nodes[current].next; } }

public boolean remove(String element) // Removes an element e from this list such that e.equals(element) // and returns true; if no such element exists, returns false { int hold; // To remember removed node index find(element); if (found) { hold = location; if (list == location) list = nodes[list].next; // remove first node else nodes[previous].next = nodes[location].next; freeNode(hold); numElements--; } return found; }

@Override public boolean contains(String element) { find(element); return found; }

@Override public String get(String element) { find(element); if (found) return nodes[location].info;

return null; }

@Override public void reset() { currentPos = list; }

@Override public String getNext() { int current = currentPos; currentPos = nodes[current].next; return nodes[current].info; }

@Override public int size() { return numElements; }

/* we cannot do enlarge in this implementation */ public void add(String element) { if (isFull()) return;

int newNode = getNode(); nodes[newNode].info = element; nodes[newNode].next = list; list = newNode; } }

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Here is what is in the Course class. The last four methods need implementation.

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public class Course { String name; int courseID; int numStudents; protected static final int NUL = -1; // End of list symbol protected class AGradeListNode { private float grade; private Student student; private int next; // A link to the next node on the list } protected AGradeListNode[] nodes; // Array of AListNode holds the linked list protected int list; // Reference to the first node on the list protected int free; // Reference to the first node on the free list // set by find method protected boolean found; // true if element found, else false protected int location; // node containing element, if found protected int previous; // node preceding location public Course(int maxNumStudents) { nodes = new AGradeListNode[maxNumStudents]; for (int index = 0; index < maxNumStudents; index++) nodes[index] = new AGradeListNode(); for (int index = 1; index < maxNumStudents; index++) nodes[index - 1].next = index; nodes[maxNumStudents - 1].next = NUL; list = NUL; free = 0; numStudents = 0; } public void addStudentGrade(Student stu, float grade) { } public void removeStudentGrade(Student stu) { } public void updateStudentGrade(Student stu, float grade) { } public float findStudentGrade(Student stu) { return -1; } }