Peek Front Element of Queue in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to return the front element of the queue.

DSA C

int peekFront(struct Queue* q) {
    if (q->front == -1) {
        return -1; // Queue is empty
    }
    return q->array[q->[1]];
}

Drag options to blanks, or click blank then click option'

Acapacity

Brear

Csize

Dfront

Attempts:

3 left

💡 Hint

Common Mistakes

Using q->array[q->rear] instead of q->array[q->front]

Returning q->size or q->capacity instead of an element

Not checking if the queue is empty before accessing

The front element of the queue is at index 'front' in the array.

2fill in blank

medium

Complete the code to check if the queue is empty before peeking.

DSA C

int peekFront(struct Queue* q) {
    if (q->[1] == -1) {
        return -1; // Queue is empty
    }
    return q->array[q->front];
}

Drag options to blanks, or click blank then click option'

Arear

Bsize

Cfront

Dcapacity

Attempts:

3 left

💡 Hint

Common Mistakes

Checking rear instead of front for emptiness

Checking size or capacity which may not reflect emptiness

Not returning -1 when queue is empty

The queue is empty if the front index is -1.

3fill in blank

hard

Fix the error in the peek function to correctly handle empty queue.

DSA C

int peekFront(struct Queue* q) {
    if ([1]) {
        return -1; // Queue is empty
    }
    return q->array[q->front];
}

Drag options to blanks, or click blank then click option'

Aq->rear == -1

Bq->front == -1

Cq->front == q->rear

Dq->size == 0

Attempts:

3 left

💡 Hint

Common Mistakes

Checking front == 0 instead of front == -1

Using rear or size incorrectly to check emptiness

The queue is empty when front is -1, not 0.

4fill in blank

hard

Fill both blanks to correctly implement peekFront with empty check and return front element.

DSA C

int peekFront(struct Queue* q) {
    if (q->[1] == -1) {
        return -1; // Queue is empty
    }
    return q->array[q->[2]];
}

Drag options to blanks, or click blank then click option'

Afront

Brear

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using rear instead of front for empty check

Returning element at rear instead of front

Check if front is -1 to detect empty queue, then return element at front index.

5fill in blank

hard

Fill all three blanks to implement peekFront with empty check, return front element, and print error if empty.

DSA C

int peekFront(struct Queue* q) {
    if (q->[1] == -1) {
        printf("[2]\n");
        return [3];
    }
    return q->array[q->front];
}

Drag options to blanks, or click blank then click option'

Afront

BQueue is empty

C-1

Drear

Attempts:

3 left

💡 Hint

Common Mistakes

Not printing error message when queue is empty

Returning wrong error code

Checking wrong index for emptiness

Check front == -1 for empty, print message, and return -1 as error code.