Array Traversal in AP CSA

Traversal means visiting every element in an array. The AP exam tests two traversal styles: the standard for loop (gives you index access) and the enhanced for-each loop (simpler, read-only).

Standard for Loop

Use when you need the index — to modify elements, compare neighbors, or traverse backwards.

int[] scores = {85, 92, 78, 95, 88};

// Forward traversal
for (int i = 0; i < scores.length; i++) {
    System.out.println(scores[i]);
}

// Backward traversal
for (int i = scores.length - 1; i >= 0; i--) {
    System.out.println(scores[i]);
}

Enhanced for-each Loop

Use when you only need to read values — cleaner syntax, but no index and cannot modify the array elements.

for (int score : scores) {
    System.out.println(score);  // read-only
    // score = 100;  // does NOT change the array!
}

int[] arr = {2, 4, 6, 8};
int result = 0;
for (int i = arr.length - 1; i >= 0; i--) {
    result += arr[i];
    if (result > 10) {
        break;
    }
}
System.out.println(result);