Error_handling_in_linked_list.cpp

#include <bits/stdc++.h>
using namespace std;

class Node
{
public:
    int val;
    Node *next;

    Node(int val)
    {
        this->val = val;
        this->next = NULL;
    }
};

void print_linked_list(Node *head)
{
    cout << "Your Linked List: ";
    Node *tmp = head;
    while (tmp != NULL)
    {
        cout << tmp->val << " ";
        tmp = tmp->next;
    }
    cout << endl;
}

void insert_at_tail(Node *&head, int v)
{
    Node *newNode = new Node(v);
    if (head == NULL)
    {
        head = newNode;
        return;
    }

    Node *tmp = head;
    while (tmp->next != NULL)
    {
        tmp = tmp->next;
    }
    tmp->next = newNode;
}

void insert_at_position(Node *head, int pos, int v)
{
    Node *newNode = new Node(v);
    Node *tmp = head;
    for (int i = 1; i <= pos - 1; i++)
    {
        tmp = tmp->next;
        if (tmp == NULL)
        {
            cout << "Invalid Index" << endl;
            return;
        }
    }
    newNode->next = tmp->next;
    tmp->next = newNode;
    cout << "Inserted at Position:- " << pos << endl;
}

void insert_at_head(Node *&head, int v)
{
    Node *newNode = new Node(v);
    newNode->next = head;
    head = newNode;
    cout << endl
         << "Inserted at Head" << endl;
}

void delete_from_position(Node *head, int pos)
{
    Node *tmp = head;
    for (int i = 1; i <= pos - 1; i++)
    {
        tmp = tmp->next;
        if (tmp == NULL)
        {
            cout << endl
                 << "Invalid Index" << endl
                 << endl;
            return;
        }
    }
    if (tmp == NULL)
    {
        cout << endl
             << "Invalid Index" << endl
             << endl;
        return;
    }
    Node *deleteNode = tmp->next;
    tmp->next = tmp->next->next;
    delete deleteNode;
}

void delete_head(Node *&head)
{
    if (head == NULL)
    {
        cout << endl
             << "Head is not available" << endl
             << endl;
        return;
    }
    Node *deleteNode = head;
    head = head->next;
    delete deleteNode;
    cout << endl
         << "Head Deleted Successfully!" << endl
         << endl;
}

int main()
{
    Node *head = NULL;
    while (true)
    {
        cout << "Option 1: Insert at Tail" << endl;       // done
        cout << "Option 2: Print Linked List" << endl;    // done
        cout << "Option 3: Insert at Position" << endl;   // done
        cout << "Option 4: Insert at Head" << endl;       // done
        cout << "Option 5: Delete from Position" << endl; // done
        cout << "Option 6: Delete Head" << endl;          // done
        cout << "Option 7: Terminate" << endl;            // done
        int op;
        cin >> op;
        if (op == 1)
        {
            cout << "Insert Value: ";
            int v;
            cin >> v;
            insert_at_tail(head, v);
        }
        else if (op == 2)
        {
            print_linked_list(head);
        }
        else if (op == 3)
        {
            int pos, v;
            cout << "Enter Position: ";
            cin >> pos;
            cout << "Enter Value: ";
            cin >> v;
            if (pos == 0)
                insert_at_head(head, v);
            else
                insert_at_position(head, pos, v);
        }
        else if (op == 4)
        {
            cout << "Enter Value: ";
            int v;
            cin >> v;
            insert_at_head(head, v);
        }
        else if (op == 5)
        {
            int pos;
            cout << "Enter Position: ";
            cin >> pos;
            if (pos == 0)
                delete_head(head);
            else
                delete_from_position(head, pos);
        }
        else if (op == 6)
        {
            delete_head(head);
        }
        else if (op == 7)
        {
            break;
        }
    }

    return 0;
}