Java Variable types Homework Help

Java Variable types:

A variable is a container it holds the value. The variable must assign with data types. Depends on it holds the memory and value.

Variable declaration and initialization:

Data type variable = value , variable1 = value…

Example:

int x, y; // Declares two ints, x, y.

int x = 100, b = 20; // Example of initialization

float A = 12; // initializes a float type variable A.

char b = 'b'; // the char variable b is initialized with value 'b'

There are three categories of variables available in java.

1. Local variables

2. Instance variables

3. Static variables

Local variables:

It is declared inside method of the class. We cannot access it outside from the class. For the local variable we have to assign the value there is no default value.

Example:

public class sample
 {
 public void agecalc()
 {
 int x = 0;
 x = x + 5;
 system.out.print(" age of person is : " + x);
 }
 public static void main(String args[]) {
 sample obj1 = new sample();
 obj1.agecalc();
 }
}

Output:

age of person is : 5

Instance variable:

It is defined without keyword STATIC keyword. It is defined outside method declaration. These variables are created when object created and destroyed when object is destroyed.

Example:

public class student
 {
 public String name;
 private float mark;
 public student (String sname)
 {
 name = sname;
 }
 // The mark value is assigned.
 public void getmark(float smark)
 {
 mark = smark;
 }
 public void printstu()
 {
 System.out.println("name : " + name );
 System.out.println("mark :" + mark);
 }
 public static void main(String args[]) {
 student s1 = new student("mani");
 s1.getmark(100);
 s1.printstu();
 }
}

Output:

name : mani

mark : 100.0

Static Variables:

It is declared with keyword STATIC. It is access by class name. It is initialized first only once. It is also known as class variable.

Example:

 public class student
{
 // mark variable is private and static
 private static float mark;
 // subject is a constant
 public static final String SUBJECT = "Tamil";
 public static void main(String args[])
 {
 mark = 75;
 System.out.println(SUBJECT + "average Mark:" + mark);
 }
}

Output:

Tamil average mark: 75