Please help me with a Java question. I have a project for Java and it asks me to

Question

Please help me with a Java question.

I have a project for Java and it asks me to build a member class and an ArrayList class.

The member class should include objects with appropriate data, constructor, access (get) and mutate (set) functions. like String of IDNumber and Name.

For the ArrayList class, it should store Member objects. It also should also have the functions to add, delete, and modify.

I have having trouble with creating an ArrayList to store objects from the Member class. Please help, thank you!

Explanation / Answer

Solution:

###Member.java

public class Member {
   //Member class fields
   private String IDNumber;
   private String Name;
  
   //Parameterized constructor
   public Member(String Name, String IDNumber) {
       this.Name = Name;
       this.IDNumber = IDNumber;
   }

   //Getters and Setters
   public String getIDNumber() {
       return IDNumber;
   }

   public void setIDNumber(String iDNumber) {
       IDNumber = iDNumber;
   }

   public String getName() {
       return Name;
   }

   public void setName(String name) {
       Name = name;
   }
  
   //Overriding toString method to display name and Id number of member objects
   @Override
   public String toString() {
       return "Member IDNumber=" + IDNumber + ", Name=" + Name;
   }
  
}

######ArrayList.java

import java.util.Scanner;

public class ArrayList {
   //Creating an array of Member class to store member type data
   Member members[] = new Member[100];
   int arraySize = 0; //To keep track of size of array
  
   //Creating a scanner object to get the input from the user
   Scanner scan = new Scanner(System.in);
  
   //Add function will add member object to the array
   public void add(Member member) {
       members[arraySize] = member;
       arraySize++;
   }
  
   //Delete method will delete the passed member from the array
   public void delete(Member member) {
       //Iterating through the array where that member matches we replace it with null
       for (int i=0; i<arraySize; i++) {
           if(members[i] == member) {
               members[i] = null;
           }
       }
   }
  
   //Modify method will allow the user to modify the contents of the member object
   public void modify(Member member) {
       //Iterating through the array
       for (int i=0; i<arraySize; i++) {
           //When the passed member matches
           if(members[i] == member) {
               //Prompting user for the name and id
               System.out.println("Enter the Name: ");
               member.setName(scan.nextLine());//Setting name
               System.out.println("Enter the ID Number");
               member.setIDNumber(scan.nextLine());//Setting Id
           }
       }
   }
  
   //Displaying the contents of the array
   public void display() {
       //Iterating over the array
       for(int i=0; i<arraySize; i++) {
           //When object is null we are skipping it
           if(members[i] != null)
               System.out.println(members[i]+" ");
       }
   }
  
   //main execution starts here
   public static void main(String[] args) {
       //Creating 4 objects with dummy data
       Member member1 = new Member("Tom", "TOM101");
       Member member2 = new Member("Tony Stark", "IronMan123");
       Member member3 = new Member("James Bond", "James007");
       Member member4 = new Member("SpiderMan", "Spider020");
      
       ArrayList membersList = new ArrayList(); //Creating a object of ArrayList class
       //to call other member functions of this ArrayList class because they are not static
       //We can't call non-static members inside a static function
      
       //Adding all the members to the array
       membersList.add(member1);
       membersList.add(member2);
       membersList.add(member3);
       membersList.add(member4);
      
       //Displaying array contents
       System.out.println("Dislaying initial members added to the arraylist");
       membersList.display();
      
       //Deleting member1
       membersList.delete(member1);
      
       //Displaying after deleting
       System.out.println("Displaying array contents after deleting member1");
      
       membersList.display();
      
       //Modifying member4 contents
       membersList.modify(member4);
      
       //Displaying after modifying
       System.out.println("Displaying array contents after modifying member4");
       membersList.display();
      
      
   }
  
  
}

Sample Run:

Dislaying initial members added to the arraylist
Member
IDNumber=TOM101, Name=Tom
Member
IDNumber=IronMan123, Name=Tony Stark
Member
IDNumber=James007, Name=James Bond
Member
IDNumber=Spider020, Name=SpiderMan
Displaying array contents after deleting member1
Member
IDNumber=IronMan123, Name=Tony Stark
Member
IDNumber=James007, Name=James Bond
Member
IDNumber=Spider020, Name=SpiderMan
Enter the Name:
Superman
Enter the ID Number
Super009
Displaying array contents after modifying member4
Member
IDNumber=IronMan123, Name=Tony Stark
Member
IDNumber=James007, Name=James Bond
Member
IDNumber=Super009, Name=Superman

Note: If you have any doubt please do comment below before giving any negative feedback. thanks.

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