link printf

procedure main()
   &window := open("B&W noise 320x240","g","size=320,240","bg=white","fg=black") |
              stop("Open window failed ")
   runtime := 10 # seconds to run
   sec := &now
   frames := 0
   until (&now - sec) >= runtime do {
      s := "320,#"
      every 1 to 240 & 1 to 320/4 do s ||:= ?"0123456789ABCDEF"
      DrawImage(0,0,s)
      frames +:= 1
      }
   sec := &now - sec
   printf("frames=%d, elapsed time=%r, fps=%r\n",frames,sec, frames/real(sec))
   Event()   # wait for any window event
   close(&window)
end