cpp_basics.cpp

/// Files handling

int main()
{
    fstream new_file;

    new_file.open("new_file.txt", ios::in);

    if (!new_file.is_open())
        cout << "No such file";
    else
    {

        while (!new_file.eof())
        {
            char ch;
            ch = new_file.get();
            cout << ch;
        }
    }

    new_file.close();

    return 0;
}

/////


/// linked list

struct Node
{
    int data;
    Node *next;
};

class LinkedList
{
private:
    Node *head;
    Node *tail;

public:
    LinkedList()
    {
        head = NULL;
        tail = NULL;
    }
    void add_node(int n)
    {
        Node *temp = new Node;
        temp->data = n;
        temp->next = NULL;

        if (head == NULL)
        {
            head = temp;
            tail = temp;
        }
        else
        {
            tail->next = temp;
            tail = temp;
        }
    }
    void get_list()
    {
        Node *temp = head;
        while (temp != NULL)
        {
            cout << temp->data << " ";
            temp = temp->next;
        }
        cout << endl;
    }

    bool search(int n)
    {
        Node *temp = head;
        while (temp != NULL)
        {
            if (temp->data == n)
            {
                return true;
            }
            temp = temp->next;
        }
        return false;
    }

    void sort()
    {
        Node *temp = head;
        Node *temp2 = head;
        Node *temp3 = head;
        int temp_data;
        while (temp != NULL)
        {
            temp2 = temp;
            while (temp2 != NULL)
            {
                if (temp->data > temp2->data)
                {
                    temp_data = temp->data;
                    temp->data = temp2->data;
                    temp2->data = temp_data;
                }
                temp2 = temp2->next;
            }
            temp = temp->next;
        }
    }
    void delete_node(int n)
    {
        Node *temp = head;
        Node *temp2 = head;
        if (temp->data == n)
        {
            head = temp->next;
            delete temp;
            return;
        }
        while (temp != NULL)
        {
            if (temp->data == n)
            {
                temp2->next = temp->next;
                delete temp;
                return;
            }
            temp2 = temp;
            temp = temp->next;
        }
    }
};

int main()
{
    LinkedList list;
    list.add_node(2);
    list.add_node(1);
    list.add_node(3);

    list.get_list();

    // cout << "Does 2 exists in a linked list: " << list.search(2) << endl;
    // cout << "Does 100 exists in a linked list: " << list.search(100) << endl;

    // list.sort();

    // list.get_list();

    // list.delete_node(2);

    // list.get_list();

    return 0;
}

///// 


/// merge arrays

void mergeArrays(int arr1[], int arr2[], int n1,
                 int n2, int arr3[])
{
    int i = 0, j = 0, k = 0;

    // Traverse both array
    while (i < n1 && j < n2)
    {
        // Check if current element of first
        // array is smaller than current element
        // of second array. If yes, store first
        // array element and increment first array
        // index. Otherwise do same with second array
        if (arr1[i] < arr2[j])
            arr3[k++] = arr1[i++];
        else
            arr3[k++] = arr2[j++];
    }

    // Store remaining elements of first array
    while (i < n1)
        arr3[k++] = arr1[i++];

    // Store remaining elements of second array
    while (j < n2)
        arr3[k++] = arr2[j++];
}

// main function code
int main()
{
    // declaring the variables for the program
    int arr1[] = {1, 3, 5, 9, 2, 7};
    int n1 = sizeof(arr1) / sizeof(arr1[0]);

    int arr2[] = {2, 4, 6, 8};
    int n2 = sizeof(arr2) / sizeof(arr2[0]);

    int arr3[n1 + n2];
    mergeArrays(arr1, arr2, n1, n2, arr3);

    cout << "Array after merging: ";
    for (int i = 0; i < n1 + n2; i++)
        cout << arr3[i] << " ";

    return 0;
}

////