Question

import java.util.LinkedList;

public class StudentLinkedList { public static void main(String[] args) { LinkedList<Student> linkedlist = new LinkedList<Student>(); 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); } 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] = quizes; 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; } }

1- What is the content of the linkedList after the executing the following program?

2- 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: o 0: Quizzes o 1: Midterm Exam o 2: Final Exam

Answer 1

Code

import java.util.Collections;
import java.util.LinkedList;
import java.util.ListIterator;

public class StudentLinkedList
{
static LinkedList<Student> linkedlist = new LinkedList<Student>();
public static void main(String[] args)
{
  
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();
System.out.println("\n\nAfter deleting the studet with id 2011103 list is.");
deleteStudentByID(20111031);
printStudentList();
sortListByID();
System.out.println("\n\nAfter sorted by the ID list is : ");
printStudentList();
findMarksAverage();
System.out.println("\n");
findMinMark(0);
System.out.println("\n");
findMinMark(1);
System.out.println("\n");
findMinMark(2);
}

private static void printStudentList()
{
for(int num=0; num<linkedlist.size(); num++)
{
System.out.println(linkedlist.get(num));
}
}

private static void deleteStudentByID(int id)
{
for(int num=0; num<linkedlist.size(); num++)
{
if(linkedlist.get(num).getID()==id)
{
linkedlist.remove(num);
return;
}
}
}

private static void sortListByID() {
Collections.sort(linkedlist);
}

private static void findMarksAverage() {
double sum=0;
for(int num=0; num<linkedlist.size(); num++)
{
int studentMarkSum[]=linkedlist.get(num).getMarks();
sum+=(studentMarkSum[0]+studentMarkSum[1]+studentMarkSum[2]);
}
System.out.println("\nThe average marks of all student is : "+sum/linkedlist.size());
}

private static void findMinMark(int i) {
int minMarks,minId=0;
int marks[]=linkedlist.get(0).getMarks();
switch(i)
{
  
case 0:
minMarks=marks[0];
for(int num=0; num<linkedlist.size(); num++)
{
marks=linkedlist.get(num).getMarks();

if(marks[0]<minMarks)
{
minMarks=marks[0];
minId=num;
}
}
System.out.println(linkedlist.get(minId).getName()+" has minimum marks in Quizzes is "+minMarks);
break;
case 1:
minMarks=marks[1];
for(int num=0; num<linkedlist.size(); num++)
{
marks=linkedlist.get(num).getMarks();
if(marks[1]<minMarks)
{
minMarks=marks[1];
minId=num;
}
}
System.out.println(linkedlist.get(minId).getName()+" has minimum marks in Midterm is "+minMarks);
break;
case 2:
minMarks=marks[2];
for(int num=0; num<linkedlist.size(); num++)
{
marks=linkedlist.get(num).getMarks();
if(marks[2]<minMarks)
{
minMarks=marks[2];
minId=num;
}
}
System.out.println(linkedlist.get(minId).getName()+" has minimum marks in Final Exam is "+minMarks);
break;
}
}
  
}
class Student implements Comparable<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 int compareTo(Student o)
{
       Long comparedSize = o.getID();
       if (this.ID > comparedSize) {
           return 1;
       } else if (this.ID == comparedSize) {
           return 0;
       } else {
           return -1;
       }
   }
  
@Override public String toString()
{
String temp = "student: " + "name = " + name + ", ID = " + ID + ", marks = {" + marks[0] + ", " + marks[1] + ", " + marks[2] + "}"; return temp;
}
}

output

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