CPP

pagesNumbering C++

void pushBook(BookStack *bkStack, BookNode *bkNode)
{
    if(isEmpty(bkStack))
      {
        bkStack->lastNode = bkNode;
        bkStack->lastNode->previousNode = NULL;
      }
    else
    {
        bkStack->lastNode->previousNode = bkStack->lastNode;
        bkStack->lastNode = bkNode;
    }
}
BookNode *popBook(BookStack *bkStack)
{
  BookNode *temp = new BookNode;
  if(isEmpty(bkStack))
  {
    temp = bkStack->lastNode;
    return temp;
  }
  else if(bkStack->lastNode->previousNode == NULL)
  {
    temp = bkStack->lastNode;
    bkStack->lastNode = NULL;
    return temp;
  }else
  {
    temp = bkStack->lastNode->previousNode;
    bkStack->lastNode->previousNode = NULL;
    bkStack->lastNode = temp;
    return temp;
  }
}

void displayStackElements(BookStack *bkStack)
{
  BookNode *nodePtr = new BookNode;

  nodePtr = bkStack->lastNode;

  if(isEmpty(bkStack))
  {
    cout << "Book stack is empty." << endl;
  }
  else
  {
      while(nodePtr != NULL)
        {
          cout << "
Book Name: " << nodePtr->bk.name << endl;
          cout << "Author Name: " << nodePtr->bk.authorName << endl;
          cout << "Page Numbers: " << nodePtr->bk.pagesNumber << endl;
          cout << "ISBN: " << nodePtr->bk.isbn << endl;
          cout << endl;


          nodePtr = bkStack->lastNode->previousNode;
          }
      }

}
bool isEmpty(BookStack *bkStack)
{
    bool status;

    if(bkStack->lastNode == NULL)
        status = true;
    else
        status = false;

    return status;
}

void addBook(BookStack *bkStack)
{
  BookNode *bkNode = new BookNode;
  cout << "
Enter the book name: ";
  getline(cin, bkNode->bk.name);
  cout << "Enter the Author's Name: ";
  getline(cin, bkNode->bk.authorName);
  cout << "Enter the ISBN: ";
  cin >> bkNode->bk.isbn;
  cout << "Enter the page numbers: ";
  cin >> bkNode->bk.pagesNumber;
  pushBook(bkStack, bkNode);
}

void removeBook(BookStack *bkStack)
{
  BookNode *removedNode = new BookNode;
  removedNode = popBook(bkStack);

  if(removedNode == NULL)
  {
    cout << "
No books to remove." << endl;
  }else
  {
    cout << endl << removedNode->bk.name << " was removed." << endl;
  }
}

pagesNumbering C++

int pagesNumbering(int n)
{
    int number_of_digits = 0;
    for(int i = 1; i <= n; i *= 10)
        number_of_digits += (n - i + 1);
    return number_of_digits;
} // => tiến code