void local fn DrawBalls( y as long, balls as CFArrayRef, sort as BOOL )
  long col, prevCol = 0, x = 10
  CFArrayRef cols = @[fn ColorWithSRGB(.78,.06,.18,1.0),fn ColorWhite,fn ColorWithSRGB(0,.24,.65,1.0)]
  if ( sort ) then balls = fn ArraySortedArrayUsingSelector( balls, @"compare:" )

  pen -1
  for long i = 0 to len(balls) - 1
    col = intval(balls[i])
    if ( sort == YES )
      if ( col != prevCol ) then y += 30 : x = 10
    else
      if ( i > 0 && i % 15 == 0 ) then y += 30 : x = 10
    end if
    oval fill (x,y,30,30), cols[col]
    x += 30
    prevCol = col
  next
end fn

void local fn DutchNationalFlagProblem
  window 1, @"Dutch national flag problem", (0,0,470,230)
  WindowSetBackgroundColor( 1, fn ColorWithSRGB(1.0,.61,0,1.0) )

  CFMutableArrayRef balls = fn MutableArrayNew

  text @"Menlo-Bold",, fn ColorWhite

  for long i = 0 to 29
    balls[i] = @(rnd(3)-1)
  next

  print @"Unsorted:"
  fn DrawBalls( 20, balls, NO )

  print %(3,100)@"Sorted:"
  fn DrawBalls( 120, balls, YES )
end fn

random

fn DutchNationalFlagProblem

HandleEvents