# Unit 4B - Free Response - Climbing Club A

Each coding exercise has its own folder. Open its `.java` file and press **Run** to try it. **Run Tests** checks every graded exercise in this lesson at once.

The following is part a of a free response question from 2012. It was question 1 on the exam. You can see all the free response questions from past exams at [Past AP CSA Exams](https://www.savemyexams.com/ap/computer-science/college-board/a/past-papers/).

**Question 1.** A mountain climbing club maintains a record of the climbs that its members have made. Information about a climb includes the name of the mountain peak and the amount of time it took to reach the top. The information is contained in the `ClimbInfo` class as declared below.

```java
public class ClimbInfo
{
    /**
     * Creates a ClimbInfo object with name peakName and time climbTime.
     *
     * @param peakName the name of the mountain peak
     * @param climbTime the number of minutes taken to complete the climb
     */
    public ClimbInfo(String peakName, int climbTime)
    {
        /* implementation not shown */
    }

    /**
     * @return the name of the mountain peak
     */
    public String getName()
    {
        /* implementation not shown */
    }

    /**
     * @return the number of minutes taken to complete the climb
     */
    public int getTime()
    {
        /* implementation not shown */
    }

    // There may be instance variables, constructors, and methods
    // that are not shown.
}
```

The `ClimbingClub` class maintains a list of the climbs made by members of the club. The declaration of the `ClimbingClub` class is shown below. You will write two different implementations of the `addClimb` method. You will also answer two questions about an implementation of the `distinctPeakNames` method

```java
public class ClimbingClub
{
    /**
     * The list of climbs completed by members of the club. Guaranteed not to be
     * null. Contains only non-null references.
     */
    private List<ClimbInfo> climbList;

    /** Creates a new ClimbingClub object. */
    public ClimbingClub()
    {
        climbList = new ArrayList<ClimbInfo>();
    }

    /**
     * Adds a new climb with name peakName and time climbTime to the list of
     * climbs.
     *
     * @param peakName the name of the mountain peak climbed
     * @param climbTime the number of minutes taken to complete the climb
     */
    public void addClimb(String peakName, int climbTime)
    {
        /* to be implemented in part (a) */
    }

    /**
     * @return the number of distinct names in the list of climbs
     */
    public int distinctPeakNames()
    {
        /* implementation shown in part (c) */
    }

    // There may be instance variables, constructors, and methods
    // that are not shown.
}
```

**Part a.** Write an implementation of the `ClimbingClub` method `addClimb` that stores the `ClimbInfo` objects in the order they were added. This implementation of `addClimb` should create a new `ClimbInfo` object with the given name and time. It appends a reference to that object to the end of climbList. For example, consider the following code segment.

```java
ClimbingClub hikerClub = new ClimbingClub();
hikerClub.addClimb("Monadnock", 274);
hikerClub.addClimb("Whiteface", 301);
hikerClub.addClimb("Algonquin", 225);
hikerClub.addClimb("Monadnock", 344);
```

When the code segment has completed executing, the instance variable `climbList` would contain the following entries.

![Picture of the list after the above code executes](images/climbClubA.png)

## How To Solve This

In the `addClimb` method you need to create a new `ClimbInfo` object and initialize the `peakName` and `climbTime`. How do you create a new object of a class and initialize the fields?

Once you have created the `ClimbInfo` object you want to add it in the order they were created. To do this you can add it to the end of the `climbList`. How do you add an object to the end of a list?

> Check your understanding: How would you create a new object newClimb of the ClimbInfo class, with a peakName of Everest and climbTime of 600? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/climbClubA.html#fr_climbA_1

> Check your understanding: How do you append a new item, 7, to the end of a non-empty ArrayList\<Integer> list? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/climbClubA.html#fr_climbA_2

## Try and Solve It

### Exercise 1

Complete the method `addClimb` in the `ClimbingClub` class in the code. The code includes a `main` method that will test the `addClimb` method.

> Open the `01-ClimbClubA` folder and edit `ClimbingClub.java`. Press **Run** to try it; **Run Tests** checks it (2 tests).

## Video - One way to code the solution

There are many possible solutions to this problem. The video below shows one solution.

The following video is also on YouTube at [https://youtu.be/dAbU9_Qn92I](https://youtu.be/dAbU9_Qn92I). It walks through coding a solution.