Loops

while Loop

A while loop runs as long as a condition is true.

int i = 0;

while (i < 5) {
    System.out.println(i);
    i++;
}

for Loop

A for loop is useful when you know how many times something should repeat.

for (int i = 0; i < 5; i++) {
    System.out.println(i);
}

Enhanced for Loop

This loop goes through every element in a collection.

String[] motors = {
    "frontLeft",
    "frontRight",
    "backLeft",
    "backRight"
};

for (String motor : motors) {
    System.out.println(motor);
}

break

break exits a loop immediately.

for (int i = 0; i < 10; i++) {

    if (i == 5) {
        break;
    }

    System.out.println(i);
}

continue

continue skips the rest of the current iteration.

for (int i = 0; i < 5; i++) {

    if (i == 2) {
        continue;
    }

    System.out.println(i);
}

FTC Example

Most FTC programs don't use loops like these very often because the SDK repeatedly calls methods such as loop() or runOpMode() for you. However, loops are still useful when processing arrays, lists, or performing calculations.

Key Takeaways

• while loops repeat while a condition is true.
• for loops repeat a set number of times.
• Enhanced for loops iterate through collections.
• break exits a loop.
• continue skips to the next iteration.