Question

In this exercise, you will create a basic data management system for students in the Department of Computer Science and Information Technology using the linked list.

You must write two classes – Student class attached, and StudentChart.

Student class consists of student data. StudentChart class contains a linked list of all students in the department.

For this purpose, you must fulfill the following interfaces (note - fields of the objects should be marked as private).

Class: Student chart

Class of Student Chart contains data for all students stored in a linked list. The way to add a student to the list by method addStudent only to the front of the list. At the beginning the student list is empty, the number of students enrolled in the Department is 0. Think what would be the fields of this class, so that you can know much information at any one time.

Constructors:

	Creat the class chart according to the private
StudentChart()	.fields(variables).

Methods:

Return type	Method name and parameters	operation
		Add student to the front of the linked list.
void	addStudent(Student student
		Delete student from the list. Do nothing if the student does not exist in the list. Returns false if student not found in the list
boolean	deleteStudent(Student student)
int	getNumOfStudents()	Returns the number of students in the list.
boolean	isStudent(Student student)	Examine if student exists in the list.
Student	getStudent(int studentNum)	Returns students data for the students with studentNum.
		Returns the student average in the course with number
double	getAverage(int course)	course
		Returns student average in all courses for all students.
double	getAverage()	(You can use the Student class methods).
		Prints the students data for all students as follow: Student number 1: <Student String representation> Student number 2: <Student String representation> … Student number <n>: <Student String representation> If there are no students print:
void	printStudentChart()	No students!

It is recommended to write tester to present all the methods of the class and to check that they actually work.

The student class :

public class Student {
   private String name;// student name
   private long id; // student identity number
   private int [] grades = new int[5]; // list of student courses grades
   
   //costructor that initialize name and id
   public Student(String name, long id){
       String n = name.toUpperCase();
       name = name.replace(name.charAt(0), n.charAt(0));
       for(int i=0 ; i<name. length(); i++)
           if(name.charAt(i)==' ')
               name = name.replace(name.charAt(i+1), n.charAt(i+1));
       this.name = name;
       this.id=id;
       
   }
   
   //copy constructor
   public Student(Student st){
       this.name= st.name;
       this.id = st.id;
   }
   
   //return the student name
   public String getName(){
       return name;
   }
   //returns the student id number
   public long getId(){
       return id;
   }
   
   // returns the course grade accoring to parameter course(course number) 
   public int getGrade(int course){
       if(grades[course]== 0)
           return -1;
       return grades[course];
       
   }
   // set the name of student with parameter name
   public void setName(String name){
       String n = name.toUpperCase();
       name = name.replace(name.charAt(0), n.charAt(0));
       for(int i=0 ; i<name. length(); i++)
           if(name.charAt(i)==' ')
               name = name.replace(name.charAt(i+1), n.charAt(i+1));
       this.name = name;
       
   }
   
   //sets the student id with parameter id
   public void setId(long id){
       this.id = id;
   }
   //set the course grade with parameter grade 
   public void setGrade(int course, int grade){
       grades[course]= grade;
   }
    // set all the grades of the student from user
   public void setGrades(int [] g){
       for(int i=0; i< grades.length; i++)
           grades[i]=g[i];
            
   }
   //returns the student average in his course
   public double getAverage(){
       int sum= 0;
       int count =0;
       for(int i=0; i< grades.length; i++){
           if(grades[i]!=-1)
          sum=+ grades[i];
           count++;
       }
       return sum/count*1.0;// compute and return average
       
   }
   
   // takes a student object as a parameter and 
   // return true if it is the same as student parameter
   public boolean equals(Student student){
       if(student.id== this.id)
           return true;
       else
           return false;
   }
   //returns a string that represents the student object
   public String toString(){
       
       String [] g = new String[5];
       for(int i=0; i< grades.length; i++)
           if(grades[i]!= -1)
               g[i]= grades[i]+" ";
               else
               g[i]="no grade";
              
       String n1= "Name:"+ name+"\n"+ "ID:  "+ id +"\n"+ "Grades:"+"\n"+
               "Introduction to Programming - "+g[0] +"\n"+"Introduction to Management – "+g[1]+"\n"+
               "Data Structures – "+g[2]+"\n"+"Introduction to Economics – "+g[3]+"\n"+
               "Introduction to Mathematics – "+g[4];
       
       return n1;               
   }
    
}

Answer 1

please find the solution for the same:-

package studentdata;

import java.util.LinkedList;

public class StudentChat {
   LinkedList<Student> list = new LinkedList<Student>();;

   public static void main(String[] args) {
       StudentChat studentChat = new StudentChat();
       studentChat.printStudentChart();
       // Adding student 1
       Student student = new Student("Rohan", 1);
       student.setGrade(0, 9);
       student.setGrade(1, 9);
       student.setGrade(2, 8);
       student.setGrade(3, 6);
       student.setGrade(4, 7);
       studentChat.addStudent(student);
       Student student2 = new Student("Raj", 2);
       student2.setGrade(0, 9);
       student2.setGrade(1, 9);
       student2.setGrade(2, 8);
       student2.setGrade(3, 6);
       student2.setGrade(4, 7);
       studentChat.addStudent(student2);
       System.out.println("Total Number of students created: " + studentChat.getNumOfSudents());
       studentChat.printStudentChart();
       System.out.println("####################");
       //getaverage
       double average=student.getAverage();
       System.out.println("total Average for student "+student.getId()+" :-"+average);
       System.out.println("####################");
       double averagecourse=student.getAverage(3);
       System.out.println("total Average for student "+student.getId()+" :-"+averagecourse);
       System.out.println("####################");
       //is valid student
       boolean isValidStudent=studentChat.isStudent(student2);
       System.out.println("Student exists:-"+isValidStudent);
       System.out.println("####################");
       // get the student
       Student stut = studentChat.getStudent(2);
       System.out.println(stut.toString());
       System.out.println("####################");
       // delete
       studentChat.deleteStudent(student2);
       studentChat.printStudentChart();
       System.out.println("####################");

   }

   public void addStudent(Student student) {
       list.addFirst(student);
   }

   public boolean deleteStudent(Student student) {
       return list.remove(student);
   }

   public int getNumOfSudents() {
       return list.size();
   }

   public boolean isStudent(Student student) {
       return list.contains(student);
   }

   public Student getStudent(int studentNum) {
       for (int i = 0; i < list.size(); i++) {
           if (list.get(i).getId() == studentNum) {
               return list.get(i);

           }
       }
       return null;
   }

   public void printStudentChart() {
       int count = list.size();
       if (count > 0) {
           for (int i = 0; i < list.size(); i++) {
               System.out.println("Student number " + list.get(i).getId());
               System.out.println(list.get(i).toString());
           }
       } else {
           System.out.println("No Students");
       }
   }

}

package studentdata;

public class Student {
   private String name;// student name
   private long id; // student identity number
   private int[] grades = new int[5]; // list of student courses grades

   // costructor that initialize name and id
   public Student(String name, long id) {
       String n = name.toUpperCase();
       name = name.replace(name.charAt(0), n.charAt(0));
       for (int i = 0; i < name.length(); i++)
           if (name.charAt(i) == ' ')
               name = name.replace(name.charAt(i + 1), n.charAt(i + 1));
       this.name = name;
       this.id = id;

   }

   // copy constructor
   public Student(Student st) {
       this.name = st.name;
       this.id = st.id;
   }

   // return the student name
   public String getName() {
       return name;
   }

   // returns the student id number
   public long getId() {
       return id;
   }

   // returns the course grade accoring to parameter course(course number)
   public int getGrade(int course) {
       if (grades[course] == 0)
           return -1;
       return grades[course];

   }

   // set the name of student with parameter name
   public void setName(String name) {
       String n = name.toUpperCase();
       name = name.replace(name.charAt(0), n.charAt(0));
       for (int i = 0; i < name.length(); i++)
           if (name.charAt(i) == ' ')
               name = name.replace(name.charAt(i + 1), n.charAt(i + 1));
       this.name = name;

   }

   // sets the student id with parameter id
   public void setId(long id) {
       this.id = id;
   }

   // set the course grade with parameter grade
   public void setGrade(int course, int grade) {
       grades[course] = grade;
   }

   // set all the grades of the student from user
   public void setGrades(int[] g) {
       for (int i = 0; i < grades.length; i++)
           grades[i] = g[i];

   }
  
   public double getAverage(int course) {
       return grades[course]*1.0;
   }

   // returns the student average in his course
   public double getAverage() {
       double sum = 0.0;
       int count = 0;
       for (int i = 0; i < grades.length; i++) {
           if (grades[i] != -1)
               sum +=grades[i];
           count++;
       }
       return sum / count;

   }

   // takes a student object as a parameter and
   // return true if it is the same as student parameter
   public boolean equals(Student student) {
       if (student.id == this.id)
           return true;
       else
           return false;
   }

   // returns a string that represents the student object
   public String toString() {

       String[] g = new String[5];
       for (int i = 0; i < grades.length; i++)
           if (grades[i] != -1)
               g[i] = grades[i] + " ";
           else
               g[i] = "no grade";

       String n1 = "Name:" + name + "\n" + "ID: " + id + "\n" + "Grades:" + "\n" + "Introduction to Programming - "
               + g[0] + "\n" + "Introduction to Management – " + g[1] + "\n" + "Data Structures – " + g[2] + "\n"
               + "Introduction to Economics – " + g[3] + "\n" + "Introduction to Mathematics – " + g[4];

       return n1;
   }

}