Arrays are one of the fundamental data structures in Java, and looping through them efficiently is a key skill for any Java developer. In this tutorial, we’ll explore different ways to iterate through an array.
for Loop
A traditional for loop is a straightforward way to loop through an array using an index.
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public class ForLoopExample { public static void main(String[] args) { int[] numbers = {10, 20, 30, 40, 50}; for (int i = 0; i < numbers.length; i++) { System.out.println(numbers[i]); } } } |
- The loop starts at
i = 0(the first index). - It runs until
i < numbers.length. - The value at
numbers[i]is printed in each iteration.
Enhanced for Loop (for-each)
The enhanced for loop, also called a for-each loop, simplifies iteration when we don’t need an index.
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public class ForEachExample { public static void main(String[] args) { int[] numbers = {10, 20, 30, 40, 50}; for (int num : numbers) { System.out.println(num); } } } |
- The loop directly assigns each array element to
numin each iteration. - No need to use an index explicitly.
while Loop
A while loop is useful when the number of iterations is not fixed beforehand.
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public class WhileLoopExample { public static void main(String[] args) { int[] numbers = {10, 20, 30, 40, 50}; int i = 0; while (i < numbers.length) { System.out.println(numbers[i]); i++; } } } |
- The loop condition
i < numbers.lengthensures we don’t go out of bounds. - We manually increment
iin each iteration.
do-while Loop
A do-while loop guarantees at least one iteration, making it useful in certain scenarios.
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public class DoWhileLoopExample { public static void main(String[] args) { int[] numbers = {10, 20, 30, 40, 50}; int i = 0; do { System.out.println(numbers[i]); i++; } while (i < numbers.length); } } |
- The loop executes at least once, even if
numbers.lengthis 0.
Streams (Java 8+)
Java Streams provide a functional approach to iterating through an array.
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import java.util.Arrays; public class StreamExample { public static void main(String[] args) { int[] numbers = {10, 20, 30, 40, 50}; Arrays.stream(numbers).forEach(System.out::println); } } |
Arrays.stream(numbers)creates a stream from the array..forEach(System.out::println)prints each element.
