C++ Dynamic Arrays Index and Capacity problems

My home work is to ask me to build a dynamic array and with other functions. I've managed to complete the rest of the problems but there is one bug I don't understand...

Currently if I set D[0]=11 and D[1]=12, no matter how big the array is, all values in the array will turned into 12, along with the capacity with it will become 12.

These are the codes I think is relevant below, I will provide more per request.

OUTPUT

template <class dynElem>
class dynarr {
  private:
    int capacity;
    dynElem *A;
  public:
    dynarr() : capacity(0), A(NULL){};
    dynarr(int N): capacity(N), A(new dynElem[N]){}
    dynarr(const dynarr<dynElem> &other);
    ~dynarr();
    dynarr<dynElem> & operator=( const dynarr<dynElem> &other);
    dynElem & operator[](int ndx) throw(InvalidIndex);
    int getCapacity();
    void reserve(int newcap);
};

template <class dynElem>
dynarr<dynElem>::dynarr(const dynarr<dynElem> &other)
{
    capacity = other.capacity;
    A = new dynElem[capacity];

    for (int i = 0; i < other.capacity; i++) {
        A[i] = other.A[i];
    }
}

template <class dynElem>
dynarr<dynElem>::~dynarr()
{
    delete[] A;
}

test.cpp

int main()
{
  dynarr<int> D(15);
  std::cout << "The capacity of D is " << D.getCapacity() << std::endl;
  D[0] = 11;
  D[1] = 12;
  std::cout << "D[0] = " << D[0] << std::endl; //12
  std::cout << "D[1] = " << D[1] << std::endl; //12
  std::cout << "The capacity of D is " << D.getCapacity() << std::endl; //12
  return 0;
}