$array = [1,67,3,12,45,2];
$count = sizeof($array);
do {
  $f=false;
  $i=0;
  foreach($array as $k=>$v) {
    if ($i==$count-1) break;
    if ($array[$i]>$array[$i+1]) {
      list($array[$i], $array[$i+1]) = [$array[$i+1], $array[$i]];
      $f=true;
    }
    ++$i;
  }//for
} while($f);
//
echo '<pre>';
print_r($array); 

$a = [1,67,3,12,45,2];
//
$cnt = sizeof($a)-1;
foreach($a as $k=>$v) {
  $end=true;
  foreach($a as $kk=>$vv) {
    if ($kk==$cnt) break;
    if ($a[$kk]>$a[$kk+1]) {
      list($a[$kk],$a[$kk+1]) = [$a[$kk+1],$a[$kk]];
      $end = false;
    }
  }//foreach
  if ($end) break;
}//foreach
//
echo '<pre>';print_r($a);