Java If-Else
Java If-Else statement is used to execute on of the two code blocks based on a given condition.
In this tutorial, we will learn the syntax and examples for If-Else statement.
Syntax
The syntax of If-Else statement is
if(condition) { //if code block } else { //else code block }
If the condition
evaluates to true
, if code block is executed.
If the condition
evaluates to false
, else code block is executed.
Flow Diagram
The following flow diagram depicts the execution flow of an if-else statement in Java.
Examples
In the following example, we are checking the condition that if x
is even. We also have an else block accompanying if block.
Main.java
public class Main { public static void main(String[] args) { int x = -2; if(x > 0){ System.out.println("x is positive."); } else { System.out.println("x is not positive."); } } }
Output
x is not positive.
In the following example, we will check if given number is even or odd, and print a message to console, using if-else statement.
Main.java
public class Main { public static void main(String[] args) { int x = 6; if(x % 2 == 0){ System.out.println("x is even."); } else { System.out.println("x is odd."); } } }
Output
x is even.
Nested If-Else Statement
Since If-Else is just another statement in Java, we can write an If-Else statement inside another If-Else statement. Since an If-Else statement is nested in another If-Else, we may call this as Nested If-Else statement.
In the following example, we have written a Nested If-Else statement.
Main.java
public class Main { public static void main(String[] args) { int a = 3; if(a % 2 == 1) { System.out.println("a is odd number."); if(a<10) { System.out.println("a is less than 10."); } else { System.out.println("a is not less than 10."); } } else { System.out.println("a is even number."); } } }
Run the program and you will get the following output in console.
Output
a is odd number. a is less than 10.
Conclusion
In this Java Tutorial, we learned how to write an If-Else statement, nested if-else statement, and presented some Java examples.