# Unit 4B - Free Response - CookieOrder B

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 a free response question from 2010. 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.** An organization raises money by selling boxes of cookies. A cookie order specifies the variety of cookie and the number of boxes ordered. The declaration of the `CookieOrder` class is shown below.

```java
public class CookieOrder
{
    /** Constructs a new CookieOrder object */
    public CookieOrder(String variety, int numBoxes)
    {
        /* implementation not shown */
    }

    /**
     * @return the variety of cookie being ordered
     */
    public String getVariety()
    {
        /* implementation not shown */
    }

    /**
     * @return the number of boxes being ordered
     */
    public int getNumBoxes()
    {
        /* implementation not shown */
    }

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

The `MasterOrder` class maintains a list of the cookies to be purchased. The declaration of the `MasterOrder` class is shown below.

```java
public class MasterOrder
{
    /** The list of all cookie orders */
    private List<CookieOrder> orders;

    /** Constructs a new MasterOrder object */
    public MasterOrder()
    {
        orders = new ArrayList<CookieOrder>();
    }

    /**
     * Adds theOrder to the master order.
     *
     * @param theOrder the cookie order to add to the master order
     */
    public void addOrder(CookieOrder theOrder)
    {
        orders.add(theOrder);
    }

    /**
     * @return the sum of the number of boxes of all of the cookie orders
     */
    public int getTotalBoxes()
    {
        /* to be implemented in part (a) */
    }

    /** Removes all cookie orders from the master order that have the same variety of
     * cookie as cookieVar and returns the total number of boxes that were removed.
     * @param cookieVar the variety of cookies to remove from the master order
     * @return the total number of boxes of cookieVar in the cookie orders removed
    */
    public int removeVariety(String cookieVar)
    { /* to be implemented in part (b) */ }

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

**Part b.** The `removeVariety` method updates the master order by removing all of the cookie orders in which the variety of cookie matches the parameter `cookieVar`. The master order may contain zero or more cookie orders with the same variety as `cookieVar`. The method returns the total number of boxes removed from the master order.

For example, consider the following code segment.

```java
MasterOrder goodies = new MasterOrder();
goodies.addOrder(new CookieOrder("Chocolate Chip", 1));
goodies.addOrder(new CookieOrder("Shortbread", 5));
goodies.addOrder(new CookieOrder("Macaroon", 2));
goodies.addOrder(new CookieOrder("Chocolate Chip", 3));
```

After the code segment has executed, the contents of the master order are as shown in the following table.

![Cookie Order Table](images/cookieOrderTable.png)

The method call `goodies.removeVariety("Chocolate Chip")` returns 4 because there were two Chocolate Chip cookie orders totaling 4 boxes. The master order is modified as shown below.

![Cookie Order Table2](images/cookieOrderTable2.png)

The method call `goodies.removeVariety("Brownie")` returns `0` and does not change the master order.

## How to Solve This

These multiple choice questions may help you write your solution.

> Check your understanding: What type of loop is best to check the variety of each cookie order in the list of orders? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/cookieOrderB.html#fr_cookieB_1

> Check your understanding: How would you remove the third item from an ArrayList\<String> list of size 6? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/cookieOrderB.html#fr_cookieB_2

> Check your understanding: How would you compare the values of two Strings str1 and str2? — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/cookieOrderB.html#fr_cookieB_3

## Mixed Up Code

> Check your understanding: The method `removeVariety` below contains the correct code for one solution to this problem, but it is mixed up. — answer it on CS Awesome: https://runestone.academy/ns/books/published/csawesome2/cookieOrderB.html#cookieOrderB

## Solve Part B

### Exercise 1

FRQ Cookie Order B: Complete the method `removeVariety`.

> Open the `01-FRQCookieOrderB` folder and edit `MasterOrder.java`. Press **Run** to try it; **Run Tests** checks it (4 tests).