JavaArrays Loop

Loop Through an Array

You can loop through the array elements with thefor loop, and use thelength property to specify how many times the loop should run.

This example creates an array of strings and then uses afor loop to print each element, one by one:

String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};for (int i = 0; i < cars.length; i++) {  System.out.println(cars[i]);}

Here is a similar example with numbers. We create an array of integers and use afor loop to print each value:

int[] numbers = {10, 20, 30, 40};for (int i = 0; i < numbers.length; i++) {  System.out.println(numbers[i]);}

Calculate the Sum of Elements

Now that you know how to work with arrays and loops, let's use them together to calculate the sum of all elements in an array:

int[] numbers = {1, 5, 10, 25};int sum = 0;// Loop through the array and add each element to sumfor (int i = 0; i < numbers.length; i++) {  sum += numbers[i];}System.out.println("The sum is: " + sum);

Loop Through an Array with For-Each

There is also a "for-each" loop, which is used exclusively to loop through elements in an array (or otherdata structures):

for (typevariable :arrayname) {  // code block to be executed}

The colon (:) is read as "in". So you can read the loop as:"for each variable in array".

The following example uses afor-each loop to print all elements in thecars array:

String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};for (String car : cars) {  System.out.println(car);}

This means:for eachString in thecars array (here calledcar), print its value.

Compared to a regularfor loop, thefor-each loop is easier to write and read because it does not need a counter (likei < cars.length). However, it only gives you the values, not their positions (indexes) in the array.

So, if you need both the position (index) of each element and its value, a regularfor loop is the right choice. For example, when printing seat numbers in a theater row, you need to show both the seat number (the index) and who is sitting there (the value):

String[] seats = {"Jenny", "Liam", "Angie", "Bo"};for (int i = 0; i < seats.length; i++) {  System.out.println("Seat number " + i + " is taken by " + seats[i]);}