ClubMembers free response answer 2021

ClubMembers is #3 from the from the 2021 AP Computer Science A Free Response problems.

https://apcentral.collegeboard.org/pdf/ap21-frq-computer-science-a.pdf?course=ap-computer-science-a

Part (a) addMembers method

public void addMembers(String[] names, int gradYear)
{
    for(String name : names)
        memberList.add(new MemberInfo(name, gradYear, true));
}

This could also be solved with a regular for loop. On the free response, when in doubt, use a regular loop (for or while).

See Enhanced for loop exercises for information on when enhanced for loops are appropriate, and to practice with them.

Part (b) removeMembers method

public ArrayList<MemberInfo> removeMembers(int year)
{
    ArrayList<MemberInfo> goodStanding = new ArrayList<MemberInfo>();	

    int i = 0;
    while(i < memberList.size())
    {
        if(memberList.get(i).getGradYear() <= year)
        {
            MemberInfo removed = memberList.remove(i);
            if(removed.inGoodStanding())
                goodStanding.add(removed);
        }
        else
            i++;
    }
            
    return goodStanding;
}

See ArrayList practice for details on adding to and removing from an ArrayList within a loop.

2021 AP CS Exam Free Response Solutions

Additional ArrayList resources

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