Java for Fucking Idiots: Learn the Basics of Java Programming Without any experience!

if
(keyPressed ==
'W'
) {
player.moveForward();
}
else if
(keyPressed ==
'A'
) {
player.moveLeft();
}
else if
(keyPressed ==
'S'
) {
player.moveBackward();
}
else if
(keyPressed ==
'D'
) {
player.moveRight();
}
else
{
player.stopMoving();
}
And behold the new and totally correct way to do it, with no mistakes
whatsoever:
switch
(keyPressed) {
case
'W'
:
player.moveForward();
case
'A'
:
player.moveLeft();

---

case
'S'
:
player.moveBackward();
case
'D'
:
player.moveRight();
default
:
player.stopMoving();
}
Whoa, crazy! We create a “switch ” with the value of the user input, then do
something different for each “case ”. And no, “case” has nothing do with
uppercase or lowercase letters; it’s when the switch equals a particular
value.
If they pressed in ‘W’, then the code under the ‘W’ case is run.
If they pressed ‘D’, then the code under the ‘D’ case is run.
The “default ” is what happens if the user input isn’t any of our cases.
Maybe they pressed space bar. Or some letter we haven’t accounted for.
Make sense? Compare it with the if/else examples further back.
However, there’s one fatal flaw in the switch example code (IT’S
ACTUALLY NOT WITHOUT MISTAKES, CURVEBALL!!!). What
happens if the user presses ‘A’? What direction does the player move?
Think about it. Scroll up/flip back/take a taxi back and look; what could be
wrong with a user pressing ‘A’? Or don’t. I’ll tell you anyway.
The player starts to 
moveLeft()
but is then immediately told to 
stopMoving()
.
“That’s what’s happened?! But why?? The user pressed ‘A’, so it matched
the ‘A’ case, right? Move left?” – you, maybe.
Well, the “
default
” line of code will actually happen every single time, in
addition to the “case”…
Because unless you specify otherwise, a switch will look at every single
‘case’, then hit the ‘default’ block of code. That switch won’t stop!

---

You need to give a very special word to Java here for each ‘case’. It’s called
a break .