Variable is a name
of reversed memory area of any values. In scala we can declare a
variable with var and val keywords.
Declare variable
with var :
Variable declare
with var can change value.This type variable called mutable.
Syntax:
var varName :
datatype = Initial value
ex: var age : int =
10
or we also use below
syntax to declare variable
var age =10
In this case we can
change the value of age.
Exampe:
object
variable
{
def
main(args:
Array[String])
{
var
age
: Int =10;
var
name
= "scala";
println("
age="+age
+"name
="+name);
//now
we will change the values og
age and name
age
=30;
name="java";
println("after
changing the values of age and name");
println("age="+
age+"name
="+name);
}
}
Output:
age=10 name
=scala
after
changing the values of age and name
age=30 name
=java
Declare variable with
val:
Variable declare
with val can not their value.This type variable called immutable.
Example:
val variableName :
datatype = Initial value
or
val varaibleName = Initial value
Example:
object
ValVaraible
{
def
main(args:
Array[String])
{
val
age
: Int =10
;
println("age="+
age);
//
age = age+10 // we can not change value of val
type varaibles
}
}
Output:
age=10
we can not change of
value of val type variable. They behavior like constant.
Multiple
assignments:
Scala support to
multiple assignments. We can assign multiple variable in a tupple.
Syntax:
val (var1: Int,
var2: String) = Pair(10, "scala")
And the type
inferencer gets it right:
val (var1, var2) =
Pair(10, "java")
Example:
object
mulAssign
{
def
main(args:
Array[String])
{
val
(val1:
Int, val2:
String)
= Pair(10,
"scala");
println("
val1 ="+val1
+"
val2 ="+
val2);
}
}
Output:
val1
=10 val2 =scala
Variable Type:
variables in scala are three type fields , method parameter and local variables.
Fields:
Fields are variables that belong to an object. The fields are accessible from inside every method in the object. Fields can also be accessible outside the object, depending on what access modifiers the field is declared with. Fields can be both val's and var's.
Method parameters:
Method parameters are variables which values are passed to a method when the method is called. Method parameters are only accessible from inside the method - but the objects passed in may be accessible from the outside, if you have a reference to the object from outside the method. Method parameters are always val's.we can say method parameter is immutable.
Local variables:
local variables are variables declared inside a method. Local variables are only accessible from inside the method, but the objects you create may escape the method if you return them from the method. Local variables can be both var's and val's
