Java Programs on Variables

 VARIABLES


Variables :

 In java we have
            1.instance  Variables 
            2.local Variables
            3.static Variables
            4.final Variables

 1.Instance  Variables: The variables which have the class level scope is called as instance variables . these are also called as class level variables . These variables can be accessed only by using the object of that particular class where the variables are present . 

 Syntax:

 For Initialization :

 <dataType> VariableName="value";

 Example:

 int a=10;

 For Declaration:

 <dataType> variableName;

 Example:

 int a;

       Program using Instance Variables

 class InstanceVariable 
{
int ivar=10;
String svar="Void Main Technologies";
float fvar=99.9f;
boolean bvar=true;

 public static void main(String[] args) 
{
InstanceVariable insVar=new InstanceVariable();

System.out.println("integer variable:"+insVar.ivar);

 System.out.println("String variable:"+insVar.svar);

 System.out.println("float variable:"+insVar.fvar);

 System.out.println("boolean variable:"+insVar.bvar);
}
}

 Save As: 

 InstanceVariable .java

 Compile:

javac InstanceVariable .java

 Run:

 java InstanceVariable 

 Output:

 integer variable=10
String variable=void Main Technologies                             
float variable=99.9
boolean variable=true.

 Note:

If Instance Variables are not initialized jvm will automatically initializes default values (eg: integer : 0, String : null).
 Program using local Variables


class LocalVariable 
{
public static void main(String[] args) 
{
int ivar=10;
String svar="Void Main Technologies";
float fvar=99.9f;
boolean bvar=true;

LocalVariable locVar=new LocalVariable();
System.out.println("integer variable:"+ivar);

System.out.println("String variable:"+svar);

System.out.println("float variable:"+fvar);

System.out.println("boolean variable:"+bvar);
}
}


Save As: 

LocalVariable .java

Compile:

javac LocalVariable .java

Run:

java LocalVariable 

Output:

integer variable=10
String variable=void Main Technologies                    
float variable=99.9
boolean variable=true

Note :

 Each and every local variable must be initialized ,else Compile Time Error.


Program using Static Variables


class StaticVariable 

{

static int ivar=10;

static String svar="Void Main Technologies";

static float fvar=99.9f;

static boolean bvar=true;



public static void main(String[] args) 

{

StaticVariable staVar=new StaticVariable();



System.out.println("integer variable:"+StaticVariable.ivar);

System.out.println("String variable:"+StaticVariable.svar);

System.out.println("float variable:"+staVar.fvar);

System.out.println("boolean variable:"+staVar.bvar);
}
}


Save As: 

LocalVariable .java

Compile:

javac StaticVariable .java

Run:

java StaticVariable 

Output:

integer variable=10
String variable=void Main Technologies                      
float variable=99.9
boolean variable=true.

 Note:

 Static Variables can either be called using className or by using Object.
Program using Final Variables

class FinalVariable 
{
final int ivar=10;
final String svar="Void Main Technologies";

 public static void main(String[] args) 
{
FinalVariable finVar=new FinalVariable();

 System.out.println("integer variable:"+finVar.ivar);

 System.out.println("String variable:"+finVar.svar);

 }

}

 Save As: 

FinalVariable .java

Compile:

javac FinalVariable .java

Run:

java FinalVariable 

Output:

integer variable=10
String variable=void Main Technologies.                              

Note:

 Final Variables must initialized with the value.
Final variable value cant be changed. 
Final variables cant be called by using className .

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