Variables in JAVA

A variable is a container that holds data, such as numbers, text, or other types of information. These variables are like labeled boxes that allow you to store and manipulate data in your programs. 

Here are some key points about variables in Java:

Variable Declaration: Before you can use a variable, you need to declare it. This means you specify its type and name. 

For example: int age; // Declaring an integer variable named "age"

Variable Initialization: After declaring a variable, you can assign a value to it.  

For example: age = 25; // Initializing the "age" variable with the value 25

Variable names should follow certain rules:

1. They must start with a letter, underscore (_), or dollar sign ($).

2. After the first character, they can include letters, numbers, underscores, and dollar signs.

3. Variable names are case-sensitive, so "age" and "Age" are different variables.

4. It's a good practice to use meaningful names that describe the variable's purpose, like "firstName" or "totalScore."

Assignment:

You can change the value of a variable by assigning it a new value.

For example: age = 26; // Changing the value of the "age" variable

Using Variables:

Once you've declared and initialized a variable, you can use it in your code. 

For example: int yearsLater = age + 5; // Using the "age" variable to calculate "yearsLater"

Scope:

Variables have a scope, which defines where they can be used. 

A variable declared inside a method is only accessible within that method.

public class VariableDemo { public static void main(String[] args) { int myAge; // Declaration myAge = 30; // Initialization int futureAge = myAge + 10; // Using variables in an expression System.out.println("My current age is " + myAge); System.out.println("In 10 years, I'll be " + futureAge); } }

In this code, we declare, initialize, and use variables to work with age-related information. Variables are fundamental in programming, allowing you to store and manipulate data to create more dynamic and useful programs.