假设$taa,$tbb,$tcc 为任意3个数字：
计算这3个数字的最大差值，
有更好的方法吗？？


if (($taa>=$tbb) and ($taa>=$tcc) and ($tbb>=$tcc) ){
$range1=$taa-$tcc;
}

if (($taa>=$tbb) and ($taa>=$tcc) and ($tcc>=$tbb) ){
$range1=$taa-$tbb;
}

if (($tbb>=$taa) and ($tbb>=$tcc) and ($taa>=$tcc) ){
$range1=$tbb-$tcc;
}

if (($tbb>=$taa) and ($tbb>=$tcc) and ($tcc>=$taa) ){
$range1=$tbb-$taa;
}


if (($tcc>=$taa) and ($tcc>=$tbb) and($taa>=$tbb) ){
$range1=$tcc-$tbb;
}

if (($tcc>=$taa) and ($tcc>=$tbb) and ($tbb>=$taa) ){
$range1=$tcc-$taa;
}