Question about Pointers and arrays

Hello. I am currently trying to make a class similar to that of the vector class. I am attempting to make a push_back function. The idea is to have an array of integers of a specified size, say like two ( int array[2] ). The push_back function would then push_back an element into this array. However, if the push_back is called three times, then a NEW array is created with double the space ( int array_two[4] ) and then the elements from the first array, are copied over to the second array. I can achieve this easily. However, I would need the first array to somehow point to the second array, while the first array ELEMENTS were deleted and the second array POINTER were deleted. The result would be a never ending supply of array space, much like a vector. Here is my sample code so far, however, it does not do what I need it to:

void vector<int>::push_back(const int& data)
{
      if(THE_ARRAY_CAPACITY > THE_SIZE_SO_FAR)
      {
            //we have room
            theDataPtr[THE_SIZE_SO_FAR] = data;
            THE_SIZE_SO_FAR++;
      }
      else
      {
            int* TempPtr = new int[(THE_ARRAY_CAPACITY*2)];
            for(unsigned int i = 0; i<THE_ARRAY_CAPACITY; i++)
            {
                  TempPtr[i] = theDataPtr[i];
            }
            THE_ARRAY_CAPACITY = THE_ARRAY_CAPACITY*2
            theDataPtr = TempPtr;
            theDataPtr[THE_SIZE_SO_FAR] = data;
            THE_SIZE_SO_FAR++;
            delete TempPtr;      
      }
}

If there is something wrong with this code, or perhaps another way to do it, help would be GREATLY appreciated.