Loops

Loops can execute a block of code as long as a specified condition is reached. They save time, reduce errors, and make code more readable.

1. while Loop

Loops through a block of code types as long as a specified condition is logical true.

while (condition) {
  // code block to be executed
}

2. do...while Loop

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);

3. for Loop

When you know exactly how many times you want to loop through a block of code, use the for loop.

// for (statement 1; statement 2; statement 3)
for (int i = 0; i < 5; i++) {
  System.out.println(i);
}

• Statement 1: Executed one time before the loop starts (Variable initialization).
• Statement 2: Defines the condition for running the loop.
• Statement 3: Executed every time after the code block has been executed (Increment/Decrement).

4. for-each Loop

Exclusively to loop through elements in an array or other collections.

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

Break and Continue

• break: Jumps out of a loop.
• continue: Breaks one iteration (in the loop), if a specified condition occurs, and continues with the next iteration in the loop.

Interactive Code

Try the standard loop vs the enhanced for-each loop!

Quiz

Next Steps

Enough small snippets. In the next module, we will learn how to organize code into reusable Methods.