do while statement in PHP with example

<?php
$a=1;
while($a<=3)
  {
  echo " number is " . $a . "<br>";
  $a++;
  }
?>

Output:
Number is 1
Number is 2
Number is 3


<?php
$a=1;
do
  {
  $a++;
  echo "The number is " . $a . "<br>";
  }
while ($a<=3);
?>


Output:
Number is 2
Number is 3
Number is 4