class?StuInfo?{
function?aaa($xm,$score){
$str='';
if(is_int($score)?||?is_float($score)){
if($score>=0?&&?$score<=100){
if($score>=90){$str='等級：A';}
else?if($score>=80){$str='等級：B';}
else?if($score>=70){$str='等級：C';}
else?if($score>=60){$str='等級：D';}
else?{$str='等級：E';}
$str='姓名：'.$xm.'，成績：'.$score.'，'.$str;
}else{
$str='輸入的值不在0-100之間！';
}
}else{
$str='輸入的值不是數值！';
}
echo?$str;
}
}
$stuinfo=new?StuInfo();
$stuinfo->aaa('張三',90);