Generating a list from a text file in PHP - php

Question

I am attempting to create an ordered list from a text file. As my code currently stands, it modifys the original text file with the input all on the same line(list number). e.g if I input "mercury" it will come out as 1. mercury, but if I input "venus", it will appear as 1.mercuryvenus
I am trying to get it to work so that if I input some text such as "mercury" and hit the submit button, it will appear as
1. mercury. If I input some more text such as "venus", it will appear as 2. venus, all in ordered list format. I assume that explode may be used for this, but I am unsure of how to implement this properly. Another option would be to create a new text file for each input if that were to be more efficient.
echo "<form method='post'>
<label>Enter some text</label><br>
<textarea name='textbox' cols='60' rows='5' required></textarea>
<br>
<input type='submit' name='submit' value='Submit'/>
<input type='hidden' name='step' value=''/>
</form>";
echo "<section>";
echo "<h3>Current tasks</h3>";
$text = ("text.txt");
$extract = (isset($_POST['textbox']) ? $_POST['textbox'] : null);
$file = fopen($text,"a");
fwrite($file,$extract);
fread($file,filesize("text.txt"));
fclose($file); #Not sure where this should really go
$c = array(file_get_contents('text.txt'));
$x = explode(" ",$c); #Could be wrong format
echo "<ol>";
foreach($c as $r) {
echo "<li>" . $r. "</li>", "<br>";
}
echo "</ol>";
echo "</section>";

Answer 1

Here is the solution
echo "<section>";
echo "<h3>Current tasks</h3>";
$text = "text.txt";
$extract = (isset($_POST['textbox']) ? $_POST['textbox'] : null);
$file = fopen($text,"a+");
fwrite($file," ".$extract);
#fread($file,filesize("$text"));
$x = explode(" ",file_get_contents($text));
if(isset($_POST['submit'])) {
echo "<ol>";
foreach ($x as $r) {
echo "<li>" . $r . "</li>", "<br>";
}
echo "</ol>";
echo "</section>"

Answer 2

First, the "a" in fopen($text,"a") means append. Which means if you already have the text "mercury" in your file and your run your program again with "venus", you will be appending "venus" on the end of "mercury" to get "mercuryvenus". If you want a space between the two, you will have to add it when your write it to file: fwrite($file, " ".$extract);
Second, you do $x = explode(... and then do not use $x in your foreach statement. Use $x instead of $c in your foreach.