`SeatingChart`

is #3 from the from the 2014 AP Computer Science A Free Response problems.

https://secure-media.collegeboard.org/digitalServices/pdf/ap/ap14_frq_computer_science_a.pdf

## Part (a) `SeatingChart`

constructor

```
public SeatingChart(List<Student> studentList, int rows, int cols)
{
seats = new Student[rows][cols];
int sIndex = 0;
for(int c = 0; c < seats[0].length; c++)
{
for(int r = 0; r < seats.length; r++)
{
if(sIndex < studentList.size())
{
seats[r][c] = studentList.get(sIndex);
sIndex++;
}
}
}
}
```

When writing a constructor for a class that stores an array or `ArrayList`

as an instance variable, make sure to actually initialize the variable. It is common for students to omit the first line entirely and incorrectly assume that adding/setting initializes the array/list. As with all constructors, make sure to initialize the instance variable rather than incorrectly declaring a new local variable.

See 2D array exercises for additional traversals and other challenges.

## Part (b) `removeAbsentStudents`

method

```
public int removeAbsentStudents(int allowedAbsences)
{
int removed = 0;
for(int r = 0; r < seats.length; r++)
{
for(int c = 0; c < seats[0].length; c++)
{
if(seats[r][c] != null && seats[r][c].getAbsenceCount() > allowedAbsences)
{
seats[r][c] = null;
removed++;
}
}
}
return removed;
}
```

## 2014 AP CS Exam Free Response Solutions

- scrambleWord and scrambleOrRemove free response solution
- Director free response solution
- Trio free response solution

## Additional resources for 2D arrays

- Intro to 2D arrays
- 2D array exercises
- Mazer free response
- Droppy free response
- Flight free response
- MatrixManipulator exercise

## Help & comments

Get help from AP CS Tutor Brandon Horn