Java Programming Tutorial - 12 - Switch Statement Video Lecture - Java

some guys is bulky welcome to twelfth
Java tutorial and in this thoron we
teach you guys about something called a
switch statement now what a switch
statement does is test one variable and
depending on the out depending on the
value of that variable pretty much that
gives you multiple choices so before we
learn the switch statement let me show
you what we had to do with our knowledge
so far say we let's make like a program
that tells you what kids do at a certain
age so say we have a program that has
variable called age and the kids age is
three right now what we would have to do
right now is make it if statement for
each age and put if age is equal to one
and then we would have to put something
like um system then we would put out and
stuff like that and it will just get
pain in the butt and then we would have
after one would put if age is equal to
two is equal to two and then do your
stuff down here as you can see we don't
want to type all that stuff for each
number so I wish there was the easier
way just to test age for a bunch of
different things well actually you don't
have to write ten different if
statements if you want to test age ten
times you can only write something
called a switch statement once and it
will give you many different options so
instead of writing ten different if
statements to see what a kid does from
ages one to ten let me show you guys
what to do what you do is write the word
is switch and what switch does is find
the variable value in the parameters so
what variable do we want to test we want
to test age so after this you just go
ahead and write curly braces and give
yourself a nice little switch body now
instead of writing on a bunch of if
statements all you would have to do is
right there called cases now what case
means is if the value of age is equal to
one what do we want to do and after case
one go ahead and put a regular :
and I don't know if you guys can see
this but this is a regular : after the
one and not a semicolon so in the case
of one um let's go ahead and
system.out.print line so what can they
do it one arm you can curl and then
after this you want to add something
called break now what break does is it
means alright if this is true in age
equals one then we have no reason to go
to the rest of the program so you can
just exit and I'll be talking about that
more later but for now just make sure
you have it so you can just repeat this
for as many options as you want so in
the case of two what do we want to
happen let's just copy this copy save
yourself some time um you can talk so in
the case of two if H equals two what do
you want to do you want to print you can
talk and then break and let's go ahead
and make one more in the case of three
again using lazy you don't feel like
typing it all in the carry case of three
you can uh get in trouble
and I know I spell trouble wrong but
just deal with it so here's what you do
you put switch and then put the variable
you want to test the value of then you
put the values that are possible after
the word case now after in the case body
what you do is write re if H is equal to
one here's what I want you to do if H is
equal to two here's what I want you to
do if H is equal to three here's what I
want you to do and the last thing you
have in every switch statement is
something called a default and to do
that you just write default and what
this does is if none of those values are
true it does a default statement so let
me scroll up a little bit so you can see
and again you don't need a value for
this like default for because it already
knows all right if everything else is
false this is where your
and do so that's why you don't need a
value so let's go ahead and all right
actually I'm gonna go ahead and copy
this since I'm lazy copy
if default let's go ahead and write um I
don't know how old your I don't know how
old you are and of course we have a
break at the end of this as well if I
can get it right break so let's go ahead
and run this with age equal to three and
let me show you guys what it does it
outputs you can get in tolerable and
it's supposed to be trouble but I typed
it wrong so and let me recap well let me
show you guys what default does so if
age isn't equal to one two or three say
Asia is equal to seven and I run this it
says I don't know how old you are so let
me recap one last time what this switch
statement does a switch statement takes
the variable whatever is in its
condition and test it so then it looks
through the cases to see what value that
variable is equal to if it's equal to
the value one it prints this if not it
doesn't do it at all then it looks if
it's equal to the value 2 if it is it
prints this if not then it skips this as
well then it looks if it's equal to the
variable 3 if it is it prints this if
not again it skips all of these and then
if it doesn't hit any one of these then
it goes default and what default means
is I ran through all these options and
none of them worked so by default I got
to do something this can't be just a
waste of a program so by default I want
you I want to output I don't know how
old you are so that is how you can use
the switch statement to test a single
variable for many different values and
this will save you a bunch of time and
keep you from writing a bunch of
different if statements and it trust me
it's a whole lot easier than writing a
bunch of if statements so that's your
basic on the switch statement um it will
save you a bunch of time so thank you
guys for watching and hopefully you
learn a little something
copy this play around with it and pretty
soon you'll be expert
it's a switch statement so again thank
you guys for watching and don't forget
to subscribe to my channel and I'll see
you next tutorial