Java Practice FRQ • 14 min read

public class MemberInfo{
    // initializes memberInfo variables
    private int gradYear;
    private String name;
    private boolean hasGoodStanding;

    // MemberInfo constructor
    public MemberInfo(String name, int gradYear, boolean hasGoodStanding){
        this.gradYear = gradYear;
        this.name = name;
        this.hasGoodStanding = hasGoodStanding;
    }
    
    // getter for gradYear
    public int getGradYear(){
        return this.gradYear;
    }
    
    // getter for the member's standing
    public boolean inGoodStanding(){
        return this.hasGoodStanding;
    }
}

public class ClubMembers{
    // ArrayList defintions
    private ArrayList<MemberInfo> memberList;
    private ArrayList<MemberInfo> newMemberList;
    private ArrayList<MemberInfo> returnList;

    // ClubMembers constructor
    public ClubMembers() {
        // Initialize the memberList ArrayList in the constructor
        memberList = new ArrayList<MemberInfo>();
        newMemberList = new ArrayList<MemberInfo>();
        returnList = new ArrayList<MemberInfo>();
    }

    // function to add new members
    public void addMembers(String[] names, int gradYear){
        //iterates through for the length of names, later does 
        for (int i = 0; i < names.length; i++){
            // creates new MemberInfo objects based on the names given and adds that to the memberList
            MemberInfo newMember = new MemberInfo(names[i], gradYear, true);
            memberList.add(newMember);
        }
        return;
    }

    // function to remove members who have graduated
    public ArrayList<MemberInfo> removeMembers(int year){
        // iterates through memberList arraylist. This syntax means each n variable is of the type MemberInfo
        for (MemberInfo n : memberList){
            //checks if the person has graduated
            if (n.getGradYear() > year){
                newMemberList.add(n);
            }
            // checks if the people who have graduated are in good standings
            else if (n.inGoodStanding()){
                returnList.add(n);
            }
        }
        // sets memberlist to the new list
        memberList = newMemberList;
        return returnList;
    }

}

// Main function for testing
public class Main{
    public static void main(String[] args) {
        ClubMembers clubMembers = new ClubMembers();
        clubMembers.addMembers(new String[]{"Toby", "Gene", "Dash"}, 2018);
        clubMembers.addMembers(new String[]{"t", "g", "d"}, 2019);
        clubMembers.addMembers(new String[]{"a", "b"}, 2020);
        clubMembers.addMembers(new String[]{"bruh",}, 2017);

        for (MemberInfo n : clubMembers.removeMembers(2018)){
            System.out.println(n.getGradYear());
        }
    }
}

Main.main(null);

2018
2018
2018
2017

Major takeaways

1. ChatGPT is very very very useful
2. ArrayList<MemberInfo(closed bracket doesn’t work). This syntax is used to create an arraylist object. An arraylist is an array-like data structure that can store objects. MemberInfo is the type of object that it can store. I didn’t know this syntax beforehand.
3. I also learned what a stringArray was. String[] is just an array of strings. I had never seen it before though
4. I learned some syntax for working with different data types, like .add(object) and .get(index) for arraylists and .length() for stringArrays
5. I also learned this syntax “for (String n : names)”. It reminded me of a forEach() loop in javascript. It esssentially iterates through each String in the stringArray called names. I later used this after learning about it in part b

// Correct code according to collegeboard

public class MemberInfo{
    // initializes memberInfo variables
    private int gradYear;
    private String name;
    private boolean hasGoodStanding;

    // MemberInfo constructor
    public MemberInfo(String name, int gradYear, boolean hasGoodStanding){
        this.gradYear = gradYear;
        this.name = name;
        this.hasGoodStanding = hasGoodStanding;
    }
    
    // getter for gradYear
    public int getGradYear(){
        return this.gradYear;
    }
    
    // getter for the member's standing
    public boolean inGoodStanding(){
        return this.hasGoodStanding;
    }
}

public class ClubMembers{
    // ArrayList defintions
    private ArrayList<MemberInfo> memberList;

    // ClubMembers constructor
    public ClubMembers() {
        // Initialize the memberList ArrayList in the constructor
        memberList = new ArrayList<MemberInfo>();
    }

    // function to add new members
    public void addMembers(String[] names, int gradYear){
        //iterates through for the length of names, later does 
        for (int i = 0; i < names.length; i++){
            // creates new MemberInfo objects based on the names given and adds that to the memberList
            MemberInfo newMember = new MemberInfo(names[i], gradYear, true);
            memberList.add(newMember);
        }
        return;
    }

    // function to remove members who have graduated
    public ArrayList<MemberInfo> removeMembers(int year){
       ArrayList<MemberInfo> removed = new ArrayList<MemberInfo>();
        for (int i = memberList.size() - 1; i >= 0; i--){
            if (memberList.get(i).getGradYear() <= year){
                if (memberList.get(i).inGoodStanding()){
                    removed.add(memberList.get(i));
                }
                memberList.remove(i);
            }
        }
        return removed;
    }

}

// Main function for testing
public class Main{
    public static void main(String[] args) {
        ClubMembers clubMembers = new ClubMembers();
        clubMembers.addMembers(new String[]{"Toby", "Gene", "Dash"}, 2018);
        clubMembers.addMembers(new String[]{"t", "g", "d"}, 2019);
        clubMembers.addMembers(new String[]{"a", "b"}, 2020);
        clubMembers.addMembers(new String[]{"bruh",}, 2017);

        for (MemberInfo n : clubMembers.removeMembers(2018)){
            System.out.println(n.getGradYear());
        }
    }
}

Main.main(null);

2017
2018
2018
2018

Checking My Answers:

a)

3/3

1. I would get this point for accessing all elements of names
2. I would get this point for instantiating a MemberInfo object with correct parameters
3. I would get this point for adding MemberInfo objects to memberList

b)

4/6

1. I’m not sure, but I thinkg I would get this point, because I do initialize an ArrayList of MemberInfo objects I just do it in other parts of the class, since I didn’t know the correct way to do it.
2. I technically would not get this point, since I don’t use get(i) and instead create a new ArrayList to replace the old memberList. I think my way would still work though? Not sure.
3. I would get this point, I call both methods
4. I think I would get this point, technically it does behave differently for three cases so I’ll give it to myself
5. I would get this point, I did identify the graduating members, well technically I identified the people not graduating
6. I wouldn’t get this point. I didn’t remove from the list, I created a new list. I guess this would use more memory or something so it’s wrong?

Crossover Comments:

• Talked to much about the code too much
• Good descriptions

Fixes:

• There isn’t much else I could do for this, I just focused on shortening my descriptions of the code for the video.