include <Array.h>
  
  include <stdexcept>
  using namespace std;
  
  // Microsoft Visual Studio requires you to omit the following line.
  // However, some compilers require it.
  //const int Array::kAllocSize;
  
  Array::Array()
  {
    mSize = kAllocSize;
    mElems = new int[mSize];
  }
  
  Array::~Array()
  {
    delete [] mElems;
  }
  
  void Array::resize(int newSize)
  {
    int* newElems = new int[newSize]; // Allocate the new array of the new size
  
    // The new size is always bigger than the old size
    for (int i = 0; i < newSize; i++) {
      // Copy the elements from the old array to the new one
      newElems[i] = mElems[i];
    }
    mSize = newSize; // store the new size
    delete [] mElems; // free the memory for the old array
    mElems = newElems; // Store the pointer to the new array
  }
  
  int& Array::operator[](int x)
  {
    if (x < 0) {
      throw out_of_range("");
    }
    if (x >= mSize) {
      // Allocate kAllocSize past the element the client wants
      resize (x + kAllocSize);
    }
    return (mElems[x]);
  }
  
  const int& Array::operator[](int x) const
  {
    if (x < 0 || x >=mSize) {
      throw out_of_range("");
    }
    return (mElems[x]);
  }