How to declare variable in Java with example?

How to declare variable in Java with example?

I'll respond in English since you specifically asked for it.

In Java, declaring a variable is a fundamental step in programming. A variable declaration specifies the type and name of a variable. Let's explore how to declare variables in Java with examples!

Basic Syntax

data_type variable_name;

Here:

Example 1: Int Variable Declaration

int myIntVariable;

In this example, we declare an integer variable named myIntVariable. The variable will store integer values.

Example 2: Double Variable Declaration

double myDoubleVariable = 3.14; // You can also initialize the variable with a value

Here, we declare a double variable named myDoubleVariable and assign it an initial value of 3.14.

Example 3: String Variable Declaration

String myStringVariable = "Hello World!";

In this example, we declare a string variable named myStringVariable and initialize it with the string literal "Hello World!".

Example 4: Boolean Variable Declaration

boolean isAdmin = true; // You can also initialize the variable with a value (false by default)

Here, we declare a boolean variable named isAdmin and assign it an initial value of true.

Example 5: Array Declaration

int[] myArrayVariable = new int[5]; // Declare an integer array of size 5

In this example, we declare an integer array named myArrayVariable with a length of 5. The array can store integer values.

Example 6: Object Reference Variable Declaration

MyClass myObjectReference = new MyClass(); // Assume MyClass is a user-defined class

Here, we declare an object reference variable named myObjectReference that references an instance of the MyClass class (assuming it exists).

Best Practices

These are just some basic examples of variable declarations in Java. With practice, you'll become more comfortable declaring variables and working with them in your programs!

How to declare variables in java example w3schools

I'll respond in English as per your request.

Declaring Variables in Java - W3Schools Example

In Java, you can declare a variable using the data type keyword followed by the name of the variable. For example:

int x; // declare an integer variable named x

Here, int is the data type and x is the variable name.

Let's see some examples:

You can assign an initial value to a variable while declaring it. For example:

int x = 10; // declare an integer variable named x and initialize it with 10

Here, the variable x is declared as an int and initialized with the value 10.

You can declare multiple variables of different data types in a single statement. For example:

int x = 10;
double y = 20.5;
boolean z = true; // declare three variables: x, y, and z

Here, the variables x, y, and z are declared with their respective data types.

You can declare an array of a specific size by using the [] operator. For example:

int[] arr = new int[5]; // declare an integer array named arr with 5 elements

Here, the variable arr is declared as an int array with 5 elements.

You can declare a multidimensional array using multiple sets of []. For example:

int[][] arr = new int[3][4]; // declare a 2D integer array named arr with 3 rows and 4 columns

Here, the variable arr is declared as a 2D integer array with 3 rows and 4 columns.

Starting from Java 10, you can use the var keyword to declare variables. The type of the variable will be inferred by the compiler based on the assignment. For example:

var x = 10; // declare an integer variable named x and initialize it with 10 (Java 10+ only)

Here, the variable x is declared using the var keyword and initialized with the value 10.

In summary, declaring variables in Java is straightforward. You can use the data type keyword followed by the name of the variable, assign an initial value, declare multiple variables, or use arrays and multidimensional arrays. The var keyword is available starting from Java 10, which allows you to declare variables with inferred types.

I hope this helps!