Circular Queue Implementation Using Array in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the front index of the circular queue.

DSA C

int front = [1];

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ANULL

B0

C-1

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing front to 0 causes confusion between empty and full states.

The front index is initialized to -1 to indicate the queue is empty.

2fill in blank

medium

Complete the condition to check if the circular queue is full.

DSA C

if ((rear + 1) % size == [1]) {
    // Queue is full
}

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Arear

Bfront

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with rear or 0 instead of front.

Not using modulo operator.

The queue is full when the next position of rear is front.

3fill in blank

hard

Fix the error in updating the rear index after enqueue operation.

DSA C

rear = (rear [1] 1) % size;

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A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction causes incorrect index movement.

Using multiplication or division is not correct for index update.

We add 1 to rear and then take modulo size to move to the next position circularly.

4fill in blank

hard

Fill both blanks to correctly update front and rear when inserting the first element.

DSA C

if (front == -1) {
    front = [1];
    rear = [2];
}

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

A0

B-1

Csize - 1

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Setting front or rear to -1 or size - 1 causes errors.

When the queue is empty, both front and rear are set to 0 for the first element.

5fill in blank

hard

Fill all three blanks to correctly dequeue an element and update front index.

DSA C

if (front == rear) {
    front = [1];
    rear = [2];
} else {
    front = (front [3] 1) % size;
}

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

A-1

B0

C+

Dsize - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Not resetting front and rear to -1 when queue becomes empty.

Using subtraction instead of addition to update front.

If front equals rear, queue becomes empty after dequeue, so both set to -1. Otherwise, front moves forward by 1 modulo size.