template <class data_type>
void sequence<data_type>::attach(data_type value){
  if(used == capacity){
        resize(used+1);
  }
  if(current_index >= used){
      start();
      advance();
      advance();
  }
  if(used!=0){
    for(int i = used; i > current_index+1; i--){
        data[i] = data[i-1];
    }
    data[current_index+1] = value;
      current_index++;
  }
    data[current_index] = value;
    ++used;

};