1.4 Variables in Java

Variable in Java -> To strore information.

Declaration: declare the data type with identifier.

                             DataType varName;

Initialization:  intialize the value with identifier

                             variableName = value;

There are 8 data type:

        1. byte

            short -> used to store numeric integer.

            int   

            long

      2. float

        double ->  used to store numeric floating point.

       3. char        -> used to store character.

           boolean -> used to store true or false.

eg:-          Declaration:

                        DataType varName;

                        int empId;

                        double empSal;

                        char empGrade;

eg:-        Initialization

                        variableName = value;

                        empId = 18331;

                        empSal = 6578.95;

                        empGrade = 'A';

Example Program 1:

class Program1

{

public static void main(String args[])

{

//variable declaration

 int empId;

 double empSal;

 char empGrade;

//variable initialization

empId = 18331;

empSal = 6578.95;

empGrade = 'A';

//print value of variable

System.out.println("Employee id is="+empId);

System.out.println("Employee Salary is="+empSal);

System.out.println("Employee Grade is="+empGrade);

}

}

Example Program 2:

class Program2

{

public static void main(String args[])

{

int x = 12;

System.out.print("x value is ="+x);

x = 34; //re-assign or re-initialization

System.out.print("x value is ="+x);

x = 45; //re-assign or re-initialization

System.out.print("x value is ="+x);

}

}

Example Program 3: 

class Program3

{

public static void main(String args[])

{

int n1 =12;

int n2 = 34;

int n3 = 45;

System.out.print("n1 value is ="+n1);

System.out.print("n2 value is ="+n2);

System.out.print("n3 value is ="+n3);

n2=n1; // copy value of n1 to n2

n3=n2 // copy value of n3 to n2

System.out.println("----------------------------------");

System.out.print("n1 value is ="+n1);

System.out.print("n2 value is ="+n2);

System.out.print("n3 value is ="+n2);

}

}

more details please follow video: