Quicksort is the new Hello World(blog.rmontanaro.com)

  #include <iterator>
  #include <algorithm> // for std::partition
  #include <functional> // for std::less
  
  template<typename RandomAccessIterator,
           typename Order>
  void quicksort(RandomAccessIterator first, RandomAccessIterator last, Order order)
  {
    if (last - first > 1)
    {
      RandomAccessIterator split = std::partition(first+1, last, std::bind2nd(order, *first));
      std::iter_swap(first, split-1);
      quicksort(first, split-1, order);
      quicksort(split, last, order);
    }
  }

  template<typename RandomAccessIterator>
 void quicksort(RandomAccessIterator first, RandomAccessIterator last)
  {
    quicksort(first, last, std::less<typename std::iterator_traits<RandomAccessIterator>::value_type>());
  }

  program qsortTest;
  const N = 1000;
  var
    a: array [0..N] of integer;
    i: integer;

  procedure quicksort(var a: array of integer; l, r: integer);
  var
    i, j, temp: integer;
    pivot: integer;
  begin
    pivot := a[(l+r) div 2]; i := l; j := r;
    while i < j do 
    begin
      while a[i] < pivot do inc(i);
      while a[j] > pivot do dec(j);
      if i <= j then 
      begin
        temp := a[i];
        a[i] := a[j];
        a[j] := temp;
        inc(i); dec(j);
      end;
    end;
    if j > l then quicksort(a, l, j);
    if i < r then quicksort(a, i, r);
  end;

  begin
    { populating the array }
    for i := 0 to N do
      a[i] := random(N);
    writeln('initial array');
    for i := 0 to N do write(a[i]:6);
    writeln;
    quicksort(a, 0, N);

    writeln;
    writeln('sorted array');
    for i := 0 to N do write(a[i]:6);
    writeln;

  end.