PHP 各种循环

<?php 
//while循环
$x=1;
  
while($x<=5) {
   echo "数字是：$x <br>";
   $x++;
} 
//foreach循环
$a = array("1","2","3","4","5"); 

foreach ($a as $b) {
  echo "$b <br>";
  }
//for循环
for ($x=0; $x<=5; $x++) {
  echo "数字是：$x <br>";
}
//do...while循环
$x=1;

do {
  echo "这个数字是：$x <br>";
  $x++;
} while ($x<=5);
?>
</body>