PHP While Loop

while(expr) {...} iterate through a loop:

<?PHP
	$ii=1;
	$sum=0;
	while($ii<5)
	{
	   $sum += $ii;
	   echo "$ii, ";
	   $ii++;
	}
	//1, 2, 3, 4, 
?>

If there is only one statement inside, the curly braces can be removed. However, if there is more than one statement, keyword endwhile can be used to end the loop, if you do not want to use curly braces.

<?PHP
	$ii=1;
	$sum=0;
	while($ii<100)
	   $sum += $ii;
	   $ii++;
	   echo "$ii\n";
	endwhile
?>

do{...} while() is almost similar to while() statement. Except that the former will execute the code one time before the condition will be checked.

<?PHP
	$ii=1;
	$sum=0;
	do
	{
	   $sum += $ii;
	   echo "$ii, ";
	   $ii++;
	}
  	while($ii<0);
	//No output 

	do
	{
	   $sum += $ii;
	   echo "$ii, ";
	   $ii++;
	}
  	while($ii<0);
	//1, 
?>