Creating a Singly Linked List from Scratch in DSA C - Code Step by Step

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the node structure for a singly linked list.

DSA C

typedef struct Node {
    int data;
    struct Node* [1];
} Node;

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

Apointer

Bprev

Clink

Dnext

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which is for doubly linked lists.

Using generic names like 'pointer' or 'link' which are uncommon.

The pointer to the next node in a singly linked list is commonly named next.

2fill in blank

medium

Complete the code to create a new node dynamically.

DSA C

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

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

ANode

Bnode

Cstruct Node

DNode*

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'node' which is undefined.

Using 'struct Node' inside sizeof without typedef.

We allocate memory for the Node structure using sizeof(Node).

3fill in blank

hard

Fix the error in the function to append a node at the end of the list.

DSA C

void appendNode(Node** head, int value) {
    Node* newNode = createNode(value);
    if (*head == NULL) {
        *head = newNode;
        return;
    }
    Node* temp = *head;
    while (temp->[1] != NULL) {
        temp = temp->next;
    }
    temp->next = newNode;
}

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

Anext

Bprev

Clink

Dpointer

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which is for doubly linked lists.

Using undefined pointer names like 'link' or 'pointer'.

To traverse the list, we follow the next pointer until it is NULL.

4fill in blank

hard

Fill both blanks to insert a node at the beginning of the list.

DSA C

void insertAtHead(Node** head, int value) {
    Node* newNode = createNode(value);
    newNode->[1] = *head;
    *head = [2];
}

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

Anext

Bhead

CnewNode

Dprev

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'prev' which is not used in singly linked lists.

Assigning head to newNode->next instead of the other way.

The new node's next points to the current head, then head is updated to the new node.

5fill in blank

hard

Fill all three blanks to print all elements of the singly linked list.

DSA C

void printList(Node* head) {
    Node* current = head;
    while (current != [1]) {
        printf("%d -> ", current->[2]);
        current = current->[3];
    }
    printf("NULL\n");
}

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

ANULL

Bdata

Cnext

Dhead

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'head' instead of NULL in the loop condition.

Printing 'next' instead of 'data'.

Moving current to 'data' instead of 'next'.

We loop until current is NULL, print current's data, then move to current->next.