1. Arrays 1. One dimensional arrays - Review 2. Using arrays
3. Two dimensional arrays

2. One Dimensional Arrays - Review
Declaring (3 different ways):
Array of Friends 1 2 3 4
Friends
John
Jane
Sally
Peter
Julie
<type> [ ] <name>; // declare array
<name> = new <type> [<num>]; // allocate space

3. One Dimensional Arrays - Review
Method 1:
String [ ] Friends; // declare array
... …
Friends = new String [5]; // allocation of space

4. One Dimensional Arrays - Review
Method 2:
String [ ] Friends = new String [5]; // declaration & // allocation of space

5. One Dimensional Arrays - Review
Method 3:
String [ ] Friends = {“John”,“Jane”, //declaration &
“Sally”, “Peter”, “Julie”}; // initialization

6. One Dimensional Arrays - Review
Using Arrays:
System.out.println(Friends[2]); // displays Sally
Friends [2] = “Myah”; // stores Myah
Friends [5] = “Thomas”;
** Out of Bounds
Error !!! **
nFriends = Friends.length; // 5

7. One Dimensional Arrays - Review
Traversing Arrays:
for ( int i=0; i<Friends.length; i++) {
System.out.println(Friends[i]); }
Output to Screen:
John
Jane
Myah
Peter
Julie

8. Two Dimensional Arrays1 2 X O
A two-dimensional array with three rows (0,1, and 2) and three columns (0,1, and 2) that represents a tic-tac-toe board. 1 2
Declaration:
<type> [ ][ ] <name>;
<name> = new <type> [<num>] [<num>];

9. Two Dimensional ArraysX O 1 2
A two-dimensional array with three rows (0,1, and 2) and three columns (0,1, and 2) that represents a tic-tac-toe board.
Declaration (3 different ways):
i) String [ ][ ] tttBoard;
tttBoard = new String [3] [3];
ii) String [ ] [ ] tttBoard = new String [3] [3];
String [ ] [ ] tttBoard = {{“X”, “O”, “”},
{“”, “O”, “X”},
{“”, “” , “” } };

10. Two Dimensional Arrays
Length Function (2-D Arrays):
rows = tttBoard.length; // 3
cols = tttBoard[0].length; // 3
Accessing Function (2-D Arrays):
tttBoard [1] [2] = “X”;
Value Stored
Row 2
Column 3

11. Two Dimensional Arrays
Traversing (2-D Arrays):
for ( int row = 0; row < tttBoard.length; row++) {
for ( int col = 0; col < tttBoard[0].length; col++) {
System.out.println(tttBoard[row][col]); }
System.out.println();
Output:
X O
O X X