Question

Write a java code :
Student ID at University is composed of year of admission and students number. we aim to implement a structure that improves operations of inserting and searching for a student. To enhance these operations, we will build a tree of linked lists (TreeOfLists) to combine advantages of both structures.
Each node in this tree contains a linked list of all students who were admitted in that year.
Each node in the linked list represents a student(id, name, GPA).
You need to :
1-Create a new class Student.
2- Use class Singly Linked List, however you need to replace data to be of type Student.
3- Build class Tree0fList that is similar to class Tree, it has the following methods:
a- insert(Student) to insert a new student. It should be inserted based on his ID in a tree node that has linked list of students in that year, if no node created yet for that year (this is the first student) then a new node should be created.
b- find( int ID) it returns a student with that ID or null.
c- remove (int id ): it searchers for student with the input id and remove his record, if that record was the last one in the linked list , then that node should be removed.
d- Print (int ): it receives an integer number represents the year and prints students name who were admitted in that year.
e- lessGPA(int x), it returns an array list of all students whose GPA is less than or equal x.
4- Test your structure in a test application (main method).

Answer 1

JAVA PROGRAM:

import java.util.ArrayList;
import java.util.Scanner;

public class University {

public static void main(String[] args) {
new University().run();
}

static class Student {

Student left = null;
Student right = null;
int id;
String name;
String address;
double GPA;

public Student(int id, String name, String address, double GPA) {
this.id = id;
this.name = name;
this.address = address;
this.GPA = GPA;
}

public String toString() {
return "Student{" + "id=" + id + ", name=" + name + ", address=" + address + ", GPA=" + GPA + '}';
}
  
}

public void run() {

Student root = new Student(123,"John","USA",20.0);
Scanner sc = new Scanner(System.in);
while(true){

System.out.println("1. insert 2. find 3. print 4. studentWithGPA 5.exit");
int choice = sc.nextInt();
  
if(choice == 1){
System.out.println("Enter id: ");
int id = sc.nextInt();
System.out.println("Enter name: ");
String name = sc.nextLine();
System.out.println("Enter Address: ");
String address = sc.nextLine();
System.out.println("Enter GPA: ");
double GPA = sc.nextDouble();
insert(root,id,name,address,GPA);
}
  

else if(choice == 2){
System.out.println("Enter id to search: ");
int id = sc.nextInt();
Student record = find(root,id);
}

else if(choice == 3){
print(root);
}
  

else if(choice == 4){
System.out.println("Enter GPA to search: ");
double GPA = sc.nextDouble();
ArrayList<Student> data = StudentWithGPA(root,GPA);
for(int i=0;i<data.size();i++){
System.out.println(data.get(i));
}
}

else{
break;
}
}
}

public void insert(Student node, int id,String name,String address,double GPA) {
if (id < node.id) {
if (node.left != null) {
insert(node.left, id,name,address,GPA);
} else {
System.out.println(" Inserted " + id + " to left of "
+ node.id);
node.left = new Student(id,name,address,GPA);
}
} else if (id > node.id) {
if (node.right != null) {
insert(node.right, id,name,address,GPA);
} else {
System.out.println(" Inserted " + id + " to right of "
+ node.id);
node.right = new Student(id,name,address,GPA);
}
}
}
  

public Student find(Student node, int id){
if(node.id == id){
return node;
}
while(node != null){
if(node.id == id){
return node;
}
else{
node = node.right;
}
}
return null;
}
  

public void print(Student node) {
if (node != null) {
print(node.left);
System.out.println(" Traversed " + node);
print(node.right);
}
}
  

public ArrayList<Student> StudentWithGPA(Student node, double GPA){
ArrayList<Student> nodes = new ArrayList<Student>();
while(node != null){
if(node.GPA <= GPA){
nodes.add(node);
}
node = node.right;
}
return nodes;
}
}