nothing sort() {

     _mergesort(0, size - 1); 
};
      void sorted() {

           _mergesort(0, N - 1);
      }; 
void sort() {

     _mergesort(0, size - 1); 
};
void mergesort(int arr[], int length) {
    //not sure why compiler complains without the ampersand
    int tmp[length];
    _mergesort(arr, 0, length, tmp);
}