C++双指针输出

C++noob有一个问题，为什么我的代码以一种方式工作，而不是以另一种方式。。我有一个带构造函数的book类，它接受一个int参数并将其设置为页数（即书中的页数）。我还有一个主.cpp.

book.h:

#ifndef BOOK_H
#define BOOK_H
#include <iostream>
#include <string>
using namespace std;
class Book{
  public:
    Book(int);
    int pages;
};
#endif

Book.cpp:

#include <iostream>
#include <string>
using namespace std;
#include "Book.h"
Book::Book(int t){
  pages = t;
}

main.cpp:

#include <iostream>
#include <string>
using namespace std;
 #include "Book.h"
Book** elements;
int size = 0;
int add(Book* b);
int main()
{
  Book* b1 = new Book(99);
  Book* b2 = new Book(100);
  Book* b3 = new Book(101);
  Book* b4 = new Book(102);
  add (b1);
  add (b2);
  add (b3);
  add (b4);
 //***I get garbage values printed here***
  cout << " pages " << elements[0]->pages << "n";
  cout << " pages " << elements[1]->pages << "n";
  cout << " pages " << elements[2]->pages << "n";
  cout << " pages " << elements[3]->pages << "n";
  //delete the books
  delete b1;
  delete b2;
  delete b3;
  delete b4;
  return 0;
}
int add(Book* b)
{
  Book* newList[size+1];
  for(int i = 0; i < size; i++)
  {
     newList[i] = elements[i];
  }
  delete elements;
  newList[size] =  b;
  elements = newList;
  //***i get correct values printed here ***
  cout << " pages in function: " << elements[size]->pages << "n";
  size++;
  return 1;
}

我的问题是，为什么当我在函数"add"中打印页面时，页面可以打印，但当我在外部打印时，却得到了垃圾值。

我的输出如下：
pages in function: 99 pages in function: 100 pages in function: 101 pages in function: 102 pages 2293484 pages 4667584 pages 4667584 pages 4667584

其中as输出应为：
pages in function: 99 pages in function: 100 pages in function: 101 pages in function: 102 pages 99 pages 100 pages 101 pages 102