Delete Node at Beginning in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to update the head pointer to the next node after deletion.

DSA C

head = [1];

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ANULL

Bhead->prev

Chead->next

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Setting head to NULL instead of head->next

Using head->prev which points backward

Not updating head at all

After deleting the first node, the head should point to the next node in the list.

2fill in blank

medium

Complete the code to free the memory of the deleted node.

DSA C

struct Node* temp = head;
head = head->next;
[1](temp);

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Adelete

Bfree

Cremove

Ddispose

Attempts:

3 left

💡 Hint

Common Mistakes

Using delete which is C++ keyword

Using remove or dispose which are not valid in C

Not freeing memory causing memory leaks

In C, free() is used to release memory allocated with malloc().

3fill in blank

hard

Fix the error in the condition to check if the list is empty before deletion.

DSA C

if ([1] == NULL) {
    printf("List is empty\n");
    return;
}

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Ahead->prev

Bhead->next

Ctemp

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Checking head->next which causes segmentation fault if head is NULL

Checking temp which may not be initialized

Checking head->prev which is irrelevant for singly linked list

To check if the list is empty, we check if the head pointer itself is NULL.

4fill in blank

hard

Fill both blanks to correctly delete the first node and update the head.

DSA C

if (head == NULL) {
    printf("List is empty\n");
    return;
}
struct Node* [1] = head;
head = [2];
free(temp);

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Atemp

Bhead->next

Chead

Dtemp->next

Attempts:

3 left

💡 Hint

Common Mistakes

Not using a temporary pointer causing loss of reference

Freeing head before updating it

Assigning head to temp instead of temp to head

We store the current head in temp, then move head to the next node before freeing temp.

5fill in blank

hard

Fill all three blanks to implement a function that deletes the first node of a singly linked list.

DSA C

void deleteAtBeginning(struct Node** [1]) {
    if (*[1] == NULL) {
        printf("List is empty\n");
        return;
    }
    struct Node* temp = *[1];
    *[2] = (*[3])->next;
    free(temp);
}

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Ahead

Dtemp

Attempts:

3 left

💡 Hint

Common Mistakes

Using single pointer instead of double pointer for head

Not dereferencing head correctly

Freeing memory before updating head

The function takes a pointer to the head pointer. We check if the list is empty by dereferencing *head. Then we update *head to point to the next node before freeing the old head.