php三个数求最大值 <?php function maxnum($a, $b, $c) { $m = $a > $b ? $a : $c; $m = $m > $c ? $m : $c; return $m; } echo maxnum(1, 7, 17); echo "\n"; function compare($a, $b, $c) { return $a > $b ? ($a > $c ? $a : $c) : ($b > $c ? $b : $c); } echo compare(1, 7, 17);