why this output is incremented before displaying

[jansky]

$i = 1;
while ($i++ <=10) // start in two $i++ = 2
{
print $i++. ','; //print first becore increment
$i++; // increment

}

just wondering
base from the document in while http://www.php.net/manual/en/control-structures.while.php

it print first before increment
i wonder why the above script
increment before printing it out

if we are going to take a look at the script above
the output should be something like
2,4,7,10

any side explanation on this?

[laserlight]

jansky wrote:

if we are going to take a look at the script above
the output should be something like
2,4,7,10

No. When you print $i, you post-increment it, hence immediately after the first printing, $i has the value of 3. You then increment it, so $i has a value of 4 when you compare it to 10. The expression that compares $i with 10 post-increments $i, thus by the second time that $i is printed, it has a value of 5, not 4.