You can loop through the array elements with the for loop, and use the length property to specify how many times the loop should run.
The following example outputs all elements in the cars array:
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
for (int i = 0; i < cars.length; i++) {
System.out.println(cars[i]);
}
Arrays are used to store multiple values in a single variable, instead of declaring separate variables for each value.
To declare an array, define the variable type with square brackets:
String[] cars;
We have now declared a variable that holds an array of strings. To insert values to it, you can place the values in a comma-separated list, inside curly braces:
String[] cars = {"Volvo", "BMW", "Ford", "Mazda"};
To create an array of integers, you could write:
int[] myNum = {10, 20, 30, 40};
You have already seen the break statement used in an earlier chapter of this tutorial. It was used to “jump out” of a switch statement.
The break statement can also be used to jump out of a loop.
This example stops the loop when i is equal to 4:
for (int i = 0; i < 10; i++) {
if (i == 4) {
break;
}
System.out.println(i);
}
To demonstrate a practical example of the for loop, let’s create a program that counts to 100 by tens:
for (int i = 0; i <= 100; i += 10) {
System.out.println(i);
}
In this example, we create a program that only print even values between 0 and 10: Continue reading Java For Loop Examples
There is also a “for-each” loop, which is used exclusively to loop through elements in an array (or other data sets):
for (type variableName : arrayName) {
// code block to be executed
}
The following example outputs all elements in the cars array, using a “for-each” loop: Continue reading Java For Each Loop
It is also possible to place a loop inside another loop. This is called a nested loop.
The “inner loop” will be executed one time for each iteration of the “outer loop”:
// Outer loop
for (int i = 1; i <= 2; i++) {
System.out.println("Outer: " + i); // Executes 2 times
// Inner loop
for (int j = 1; j <= 3; j++) {
System.out.println(" Inner: " + j); // Executes 6 times (2 * 3)
}
} When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop:
for (statement 1; statement 2; statement 3) {
// code block to be executed
}Statement 1 is executed (one time) before the execution of the code block.
Statement 2 defines the condition for executing the code block.
Statement 3 is executed (every time) after the code block has been executed.
The example below will print the numbers 0 to 4: Continue reading Java For Loop
To demonstrate a practical example of the while loop, we have created a simple “countdown” program:
int countdown = 3;
while (countdown > 0) {
System.out.println(countdown);
countdown--;
}
System.out.println("Happy New Year!!");
To demonstrate a practical example of the while loop combined with an if else statement, let’s say we play a game of Yatzy: Continue reading Java While Loop Examples
The do/while loop is a variant of the while loop. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true.
do {
// code block to be executed
}
while (condition
);
The example below uses a do/while loop. The loop will always be executed at least once, even if the condition is false, because the code block is executed before the condition is tested: Continue reading Java Do While Loop
Loops can execute a block of code as long as a specified condition is reached.
Loops are handy because they save time, reduce errors, and they make code more readable.