#4.2 Kotlin Data Types: VAR vs VAL: Variables and Constants Part-1 Video Lecture | Kotlin Tutorial for Beginners: Learn Kotlin in easy language - Back-End Programming

hi Lisa strings of the hearts once again
welcome to the next video of Cortland
programming series now in this video we
will talk about the various data types
in case of Cortland now let us take an
example suppose if I ask you to define a
value of 10 let's say it is your age
then how you are going to define the
value of 10 in case of Cortland now the
syntax to define a value or the variable
in case of Cortland is you have to use
the keyword of where var followed by
space the variable name such as age in
our case and now followed by a semicolon
and then you have to simply use the
datatype such as this 10 is actually the
integer value so I will simply use
capital I and T right followed by equal
to and then the value now remember in
Cortland at the end we do not write a
semicolon so this 10 is actually the
value this int is actually the data type
and this age is actually known as the
variable and this is the where keyword
and now the same statement can also be
written as where H equal to 10 now in
this case we are not using a semicolon
and integer datatype because just
because we are simply initializing the
variable age equal to 10 in the same
line so this age variable will
automatically become integer value now
proceeding forward
suppose if I ask you to define your name
such as my name as string so for that
again I will use where name string equal
to a string or where name equal to
shrink simply right so this is how we
will define a name of the type of string
and now at the end suppose you want to
define a boolean value such as if a
person is alive then it is true and if
the person is dead then it is false then
in that case we have where is alive
followed by colon followed by boolean
equal to true or there is alive equal to
true both are actually correct now if
you notice one thing here we have I as
capital
as capital and B as capital now in Java
we used to define boolean as small B and
integer as small I right
but in Cortland the things are little
different now the reason behind this is
that in Cortland we have all the data
types as objects that is there is no
primitive data type in case of Cortland
yes you have heard it right the Cortland
has simply removed such things that was
present in Java
everything is object in case of Cortland
now in case of Cortland we have the
boolean data type byte care short int
long float and at last we have double
now notice here we have everything in
capital such as B as capital F as
capital L is capital and so on right so
all these data types are actually
objects now what is the size of these
data types that they actually consume
when the application is up and running
so the amount of memory that they
consume is boolean as one bit byte as 8
bit and at last we have double as 64 bit
now the double and long consumes a large
amount of memory 64 bit and after that
we have int and float as 32 bit
similarly short and care as 16 bit and
so on byte and boolean and now
proceeding forward if I define some
variable of boolean or byte then what
will be the default value of datatypes
now in Cortland since they are all
objects so all objects must be
initialized to get some value right
otherwise your code will not be compiled
so in short in Cortland we do not have
any default value for these data types
now at the end what are the examples of
these data types now these are boolean
that can contain true and false as a
value byte can contain minus 127 to 128
and then these are some care values
integer values long float and double now
in case of
here you can notice we have to use the
keyboard of L right minus 2 L minus 3 L
43 L and something like that to tell the
compiler that the variable that we have
defined is actually of the type of long
now inclusive float we have to use the
keyboard of F or capital F it is totally
up to your wish right three point four F
three point seven F and so on now in
case of double we have small D and
capital D as the suffix so as to let the
compiler know that the variable is
actually of the type of double so make
sure you remember all these things right
now everything we will check out inside
the demo video but before that let me
tell you one more thing now in case of
Cortland we have where and valve now
previously we saw what is the VAD we use
vert keyword to define any variable now
apart from that we have some Val as well
that stands for the constant value now
in Cortland we have that as mutable and
Val is immutable
now what is mutable and immutable now in
case of where if you suppose define a
variable then later on in future you can
simply change the value of the variable
right but if you define some value with
the help of Val keyword then in that
case you can never change the value of
the variable later on in your
application so the Val keyword is used
to define the constant value for your
application or your class or your method
so always remember this the Val is
immutable so the value of the variable
cannot be changed later