Java else Keyword

The else keyword in Java is used in conjunction with the if keyword to create conditional statements that specify an alternative block of code to execute if the if condition is false.

Table of Contents

1. Introduction
2. else Keyword Syntax
3. Understanding else
4. Examples
   • Basic Usage
   • Using if-else
   • Using if-else if-else
5. Real-World Use Case
6. Conclusion

Introduction

The else keyword allows you to specify a block of code that will be executed if the if condition is false. This provides a way to handle both the true and false outcomes of a condition.

else Keyword Syntax

The syntax for the else statement is as follows:

if (condition) { // code to be executed if the condition is true } else { // code to be executed if the condition is false } 

Example:

if (age >= 18) { System.out.println("You are an adult."); } else { System.out.println("You are not an adult."); } 

Understanding else

The else statement is used to define a block of code that will be executed if the if condition evaluates to false. This helps in handling cases where the condition is not met.

Key Points:

• The else block is optional and follows an if block.
• Only one else block can follow an if block.

Examples

Basic Usage

To demonstrate the basic usage of the else keyword, we will check if a number is positive or not.

Example

public class ElseExample { public static void main(String[] args) { int number = -10; if (number > 0) { System.out.println("The number is positive."); } else { System.out.println("The number is not positive."); } } } 

Output:

The number is not positive. 

Using if-else

The if-else statement allows you to execute one block of code if the condition is true and another block of code if the condition is false.

Example

public class IfElseExample { public static void main(String[] args) { int temperature = 30; if (temperature > 20) { System.out.println("It is warm outside."); } else { System.out.println("It is cold outside."); } } } 

Output:

It is warm outside. 

Using if-else if-else

The if-else if-else statement allows you to check multiple conditions and execute different blocks of code based on which condition is true.

Example

public class IfElseIfExample { public static void main(String[] args) { int score = 85; if (score >= 90) { System.out.println("Grade: A"); } else if (score >= 80) { System.out.println("Grade: B"); } else if (score >= 70) { System.out.println("Grade: C"); } else if (score >= 60) { System.out.println("Grade: D"); } else { System.out.println("Grade: F"); } } } 

Output:

Grade: B 

Real-World Use Case

Checking User Input

In real-world applications, the else keyword is useful for handling user input and providing feedback based on the input.

Example

public class UserAgeCheck { public static void main(String[] args) { int age = 15; if (age >= 18) { System.out.println("You are eligible to vote."); } else { System.out.println("You are not eligible to vote."); } } } 

Output:

You are not eligible to vote. 

Conclusion

The else keyword in Java is an essential part of creating conditional statements. It allows you to specify an alternative block of code to execute when the if condition is false. By understanding and using the else keyword, you can effectively control the flow of your Java programs and handle different conditions more gracefully.