CSIS 110 - Lecture 27
Next Programming Assignment
I call it "virtual vacation". Discuss the assignment. This technique is called chromakey.
Take everyone's picture.
Question: how do we represent the image? We can use a 2-dimensional array.
Multi-dimensional arrays
We have looked at one-dimensional arrays. Java also has multidimensional arrays.
int[] quizScores = new int[20];
ChessPiece[][] chessboard = new ChessPiece[8][8];
double [][][] temperature = new double[500][500][100];
We're going to look at 2-dimensional arrays. They are the most commonly used type of
multi-dimensional array.
A typical way of thinking about 2D arrays is as a set of rows and columns. The
chessboard example has 8 rows and 8 columns. Other examples
String[][] words = new String[10][4];
double[][] measurements = new double[3][5];
First dimension is the number of rows, second dimension is number of columns.
Can anyone think of other 2-dimensional items that we could model using a 2D array?
- gameboards
- spreadsheet
- map coordinates
- matrices
- computer displays
- photographs/images
How would we define a photo as a 2D array of pixels. Let's say that it is 640 pixels wide
and 480 pixels high?
Pixel[][] photo = new Pixel[480][640];
Note that first element is number of rows (the height) and second element is number of
columns (the width).
Accessing the elements
