function nuniq = r8vec_sorted_unique_count ( n, a, tol )

%% R8VEC_SORTED_UNIQUE_COUNT counts the unique elements in a sorted R8VEC.
%
%  Discussion:
%
%    Because the array is sorted, this algorithm is O(N).
%
%  Modified:
%
%    30 April 2004
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer N, the number of elements of A.
%
%    Input, real A(N), the sorted array to examine.
%
%    Input, real TOL, a nonnegative tolerance for equality.
%
%    Output, integer NUNIQ, the number of unique elements of A.
%
  nuniq = 0;

  if ( n < 1 )
    return;
  end

  nuniq = 1;

  for i = 2 : n

    if ( tol < abs ( a(i-1) - a(i) ) )
      nuniq = nuniq + 1;
    end

  end