HTML and CSS Reference
In-Depth Information
To randomize the puzzle pieces, we first need to set up an array named
newBoard
that will
hold the randomized puzzle pieces.
newBoard
will be what we call a
parallel array
. Its pur-
pose is to become the original array—but randomized. We then create a local
cols
variable
and initialize it to the length of the
board
array that was passed in to the function, and we
create a local
rows
variable, initialized to the length of the first column—
board[0]
—in the
array. This works because all of our rows and columns are the same length, so the number of
rows in the first column is the same as all the others. We now have the building blocks re-
quired to randomize the pieces:
function
function
randomizeBoard
(
board
) {
var
var
newBoard
=
new
new
Array
();
var
var
cols
=
board
.
length
;
var
var
rows
=
board
[
0
].
length
Nextweloopthrougheverycolumnandrow,randomlychoosingapiecefromthe
board
array
and moving it into
newBoard
:
for
for
(
var
var
i
=
0
;
i
<
cols
;
i
++
) {
NOTE
We use two nested
for:next
loops here, once again.
Every time we come to an iteration of the outer nested loop, we create a new array that we
will fill up in the second nested loop. Then we drop into that nested loop. The
found
variable
will be set to
true
when we have found a random location to place the piece in the
newBoard
array. The
rndRow
and
rndCol
variables hold the random values that we will create to try and
find a random location for the puzzle pieces:
newBoard
[
i
]
=
new
new
Array
();
for
for
(
var
var
j
=
0
;
j
<
rows
;
j
++
) {
var
var
found
=
false
false
;
var
var
rndCol
=
0
;
var
var
rndRow
=
0
;
Now we need to find a location in
newBoard
in which to put the puzzle piece from the
board
array. We use a
while()
loop that continues to iterate as long as the
found
variable is
false
.
To find a piece to move, we randomly choose a row and column and then use them to see
whether that space (
board[rndCol][rndRow]
) is set to
false
. If it is not
false
, we have
found a piece to move to the
newBoard
array. We then set
found
equal to
true
so that we can
get out of the
while()
loop and move to the next space in
newBoard
that we need to fill:
