variable increment doesn't work - php

Question

When I launch my web page, increment doesn't work correctly!
It should go like this: $i = from 1 to x (0,1,2,3,4,5,6 etc..).
But instead it jumps over every step giving result of (1,3,5,7 etc..).
Why is this code doing this?
<ul class="about">
<?php
$result = mysql_query("SELECT * FROM info WHERE id = 1");
while ($row = mysql_fetch_assoc($result))
{
$bioText = $row['bio'];
}
$endBioTxt = explode("\n", $bioText);
for ($i=0; $i < count($endBioTxt);)
{
if (checkNum($i) == true)
{
echo "<li class='left'><div>".$endBioTxt[$i]."</div></li>";
echo $i;
}
else
{
echo "<li class='right'><div>".$endBioTxt[$i]."</div></li>";
echo $i;
}
$i++;
}
// Function to check if number is prime
function checkNum($num){
return ($num % 2) ? TRUE : FALSE;
}
?>
</ul>
Output:
Sometext!(right side)
0
1
Sometext2!(right side)
2
3
...

Answer 1

Please DONT do this as other suggested:
for ($i=0; $i < count($endBioTxt); $i++)
do this:
$count = count($endBioTxt);
for ($i=0; $i < $count; $i++) {
}
No need to calculate the count every iteration.
Nacereddine was correct though about the fact that you don't need to do:
$i++;
inside your loop since the preferred (correct?) syntax is doing it in your loop call.
EDIT
You code just looks 'strange' to me.
Why are you doing:
while ($row = mysql_fetch_assoc($result))
{
$bioText = $row['bio'];
}
???
That would just set $bioText with the last record (bio value) in the recordset.
EDIT 2
Also I don't think you really need a function to calculate the modulo of a number.
EDIT 3
If I understand your answer correctly you want 0 to be in the left li and 1 in the right li 2 in the left again and so on.
This should do it:
$endBioTxt = explode("\n", $bioText);
$i = 0;
foreach ($endBioTxt as $txt)
{
$class = 'left';
if ($i%2 == 1) {
$class = 'right';
}
echo '<li class="'.$class.'"><div>'.$txt.'</div></li>';
echo $i; // no idea why you want to do this since it would be invalid html
$i++;
}

Answer 2

Your for statement should be:
for ($i=0; $i < count($endBioTxt); $i++)
see http://us.php.net/manual/en/control-structures.for.php

Answer 3

$i++; You don't need this line inside a for loop, it's withing the for loop declaration that you should put it.
for ($i=0; $i < count($endBioTxt);$i++)
{
if (checkNum($i) == true)
{
echo "<li class='left'><div>".$endBioTxt[$i]."</div></li>";
echo $i;
}
else
{
echo "<li class='right'><div>".$endBioTxt[$i]."</div></li>";
echo $i;
}
//$i++; You don't need this line inside a for loop otherwise $i will be incremented twice
}
Edit: Unrelated but this isn't how you check whether a number is prime or not
// Function to check if number is prime
function checkNum($num){
return ($num % 2) ? TRUE : FALSE;
}

Answer 4

This code works, please test it in your environment and then uncomment/comment what you need.
<?php
// This is how query should look like, not big fan of PHP but as far as I remember...
/*
$result = mysql_query("SELECT * FROM info WHERE id = 1");
$row = mysql_fetch_assoc($result);
$bioText = $row['bio'];
$endBioTxt = explode("\n", $bioText);
*/
$endBioTxt[0] = "one";
$endBioTxt[1] = "two";
$endBioTxt[2] = "three";
$endBioTxt[3] = "four";
$endBioTxt[4] = "five";
$totalElements = count($endBioTxt);
for ($i = 0; $i < $totalElements; $i++)
{
if ($i % 2)
{
echo "<li class='left'><div>".$endBioTxt[$i]."</div></li>";
}
else
{
echo "<li class='right'><div>".$endBioTxt[$i]."</div></li>";
}
/*
// This is how you should test if all your array elements are set
if (isset($endBioTxt[$i]) == false)
{
echo "Array has some values that are not set...";
}
*/
}
Edit 1
Try using $endBioTxt = preg_split('/$\R?^/m', $bioTxt); instead of explode.