Queue Implementation Using Linked List in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new node with given data.

DSA C

struct Node* newNode(int data) {
    struct Node* temp = (struct Node*)malloc(sizeof(struct Node));
    temp->data = [1];
    temp->next = NULL;
    return temp;
}

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

Adata

BNULL

Ctemp

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning NULL or 0 instead of the data value.

Using the wrong variable name.

The new node's data field should be set to the input parameter 'data'.

2fill in blank

medium

Complete the code to check if the queue is empty.

DSA C

int isEmpty(struct Queue* q) {
    return (q->front == [1]);
}

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Aq->rear

B0

CNULL

Dq->front

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing front to rear instead of NULL.

Using 0 instead of NULL in pointer comparison.

The queue is empty if the front pointer is NULL.

3fill in blank

hard

Fix the error in the enqueue function to correctly update the rear pointer.

DSA C

void enqueue(struct Queue* q, int data) {
    struct Node* temp = newNode(data);
    if (q->rear == NULL) {
        q->front = temp;
        q->rear = [1];
        return;
    }
    q->rear->next = temp;
    q->rear = temp;
}

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Atemp

Bq->front

CNULL

Dq->rear

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning q->front or NULL to q->rear.

Not updating q->rear at all.

When the queue is empty, both front and rear should point to the new node 'temp'.

4fill in blank

hard

Fill both blanks to correctly dequeue an element and update the queue pointers.

DSA C

int dequeue(struct Queue* q) {
    if (isEmpty(q))
        return -1;
    struct Node* temp = q->front;
    int data = temp->data;
    q->front = [1];
    if (q->front == NULL)
        q->rear = [2];
    free(temp);
    return data;
}

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Aq->front->next

BNULL

Ctemp->next

Dq->rear->next

Attempts:

3 left

💡 Hint

Common Mistakes

Using q->front->next before updating front pointer.

Not setting rear to NULL when queue becomes empty.

After removing the front node, front should point to the next node (temp->next). If front becomes NULL, rear should also be set to NULL.

5fill in blank

hard

Fill all three blanks to print all elements in the queue from front to rear.

DSA C

void displayQueue(struct Queue* q) {
    struct Node* temp = [1];
    while (temp != [2]) {
        printf("%d -> ", [3]);
        temp = temp->next;
    }
    printf("NULL\n");
}

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Aq->front

BNULL

Ctemp->data

Dq->rear

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from rear instead of front.

Looping until temp equals rear instead of NULL.

Printing temp instead of temp->data.

Start from the front node, loop until temp is NULL, and print temp->data at each step.