Java for Loop Syntax
A for loop has three parts in parentheses, separated by semicolons: initialization, condition and update.
Java for Loop Syntax
for (initialization; condition; update) {
// statements
}
The initialization runs once, before the loop starts. The condition is checked before each iteration, and the loop ends when it is false. The update runs after each iteration and usually increments or decrements a counter. All three parts are optional: for (;;) loops forever.
Java For Loop Examples
The following are examples of the for loop in Java. Run them in the online Java code runner to see each iteration printed.
Count down with a for loop
The update can decrement the counter as well as increment it.
Java for Loop Countdown Example
public class CountdownExample {
public static void main(String[] args) {
for (int i = 3; i > 0; i--) {
System.out.println(i);
}
System.out.println("Go");
}
}
// output:
// 3
// 2
// 1
// Go
Loop through an array
Array indexes run from 0 to length - 1, so the condition is i < array.length.
Java for Loop Array Example
public class ArrayLoopExample {
public static void main(String[] args) {
int[] prices = {10, 20, 30};
int total = 0;
for (int i = 0; i < prices.length; i++) {
total += prices[i];
}
System.out.println("Total: " + total);
}
}
// output: Total: 60
Loop through a List with the enhanced for loop
The enhanced for loop, also called for-each, goes through every element of an array or a collection such as a List, without an index variable.
Java Enhanced for Loop Example
import java.util.List;
public class EnhancedForExample {
public static void main(String[] args) {
List<String> languages = List.of("PHP", "Python", "Java");
for (String language : languages) {
System.out.println(language);
}
}
}
// output:
// PHP
// Python
// Java
Loop through the characters of a String
To read a String character by character, loop from 0 to length() - 1 and call charAt().
Java for Loop String Example
public class StringCharsExample {
public static void main(String[] args) {
String word = "Java";
for (int i = 0; i < word.length(); i++) {
System.out.println(i + ": " + word.charAt(i));
}
}
}
// output:
// 0: J
// 1: a
// 2: v
// 3: a
See also