I'm new to programming and need help with loops in php. I need to make the page so that when you input two different numbers, all of the numbers in between them are displayed on the page, in a table, and if the ending number is lower than the starting number, then an error appears. Any help is appreciated.
<body>
<form method="post">
Starting Number: <br>
<input type="text" name="start" required><br><br>
Ending Number: <br>
<input type="text" name="end" required><br><br>
<input type="submit" name="subBtn"<br><br><br>
</form>
<?php
// using if statements to automatically set the grade and comment
if ($_POST['subBtn'])
// store the posted values from the form in variables
$start = $_POST['start'];
$end = $_POST['end'];
?>
<table border="1" style="width:100%" padding="15px">
<tr>
<td>Temperature (Celcius)</td>
<td>Temperature (Kelvin)</td>
<td>Temperature (Farenheit)</td>
</tr>
<tr>
<td>
<?php
$c = $start;
while($start >= $end){?>
<?php echo $start--;?>
<?php }?>
</td>
<td><?php
$k = start + 273;
while($k != $end + 272){?>
<?php echo $k--;?>
<?php }?>
</td>
<td>
<?php
$f = 212;
while($f >= 31){?>
<?php echo $f-=1.8;?>
<?php }?>
</td>
</tr>
</table>
</body>
