Need help debugging PHP program

[jameshay]

I can't figure out what's wrong with this. The program works, but the duplication doesn't work. The error I get is :

Notice: Undefined variable: SongToAdd in C:\ITEC315\htdocs\users\ramojumder0\Reinforcement Exercises\Ch. 6\R.E.6-1_SongOrganizer.php on line 64

Notice: Undefined variable: ExistingSongs in C:\ITEC315\htdocs\users\ramojumder0\Reinforcement Exercises\Ch. 6\R.E.6-1_SongOrganizer.php on line64

Warning: in_array() expects parameter 2 to be array, null given in C:\ITEC315\htdocs\users\ramojumder0\Reinforcement Exercises\Ch. 6\R.E.6-1_SongOrganizer.php on line 64

Warning: fopen(SongOrganizer/songs.txt): failed to open stream: No such file or directory in C:\ITEC315\htdocs\users\ramojumder0\Reinforcement Exercises\Ch. 6\R.E.6-1_SongOrganizer.php on line 72
There was an error saving your message!

I bolded line 64 below, which is an if (in_array ) statement.
line 64 is:

 if (in_array($SongToAdd, $ExistingSongs))
    {
        echo "<p>The song you entered already exists!<br />\n";
        echo "Your song was not added to the list.</p>";
    }
   

<?php

 if (isset($_GET['action']))
    {
        if ((file_exists("SongOrganizer/songs.txt")) 
        && (filesize("SongOrganizer/songs.txt") != 0))
        {
            $SongArray = file("SongOrganizer/songs.txt");
            
            switch ($_GET['action'])
            {
                case 'Remove Duplicates':
                    $SongArray = array_unique($SongArray);
                    $SongArray = array_values($SongArray);
                    break;
                case 'Sort Ascending':
                    sort($SongArray);
                    break;
                case 'Shuffle':
                    shuffle($SongArray);
                    break;
            } // end of switch statement
            
            if (count($SongArray)>0)
            {
                $NewSongs = implode($SongArray);
                $SongStore = fopen("SongOrganizer/songs.txt", "wb");
                if ($SongStore === false)
                    echo "There was an error updating the song file\n";
                else
                {
                    fwrite($SongStore, $NewSongs);
                    fclose($SongStore);
                }
            }
            else
                unlink("SongOrganizer/songs.txt");
        }
    }
    
    if (isset($_POST['submit']))
    {
        $SongToAdd = stripslashes($_POST['SongName']) . "\n";
        $ExistingSongs = array();
        if (file_exists("SongOrganizer/songs.txt") 
        	&& filesize("SongOrganizer/songs.txt") > 0)
        {
            $ExistingSongs = file("SongOrganizer/songs.txt");
        }
    }
    

    if (in_array($SongToAdd, $ExistingSongs))
    {
        echo "<p>The song you entered already exists!<br />\n";
        echo "Your song was not added to the list.</p>";
    }
   
    else
    {
        $SongFile = fopen("SongOrganizer/songs.txt", "ab");
        if ($SongFile === false)
            echo "There was an error saving your message!\n";
        else
        {
            fwrite($SongFile, $SongToAdd);
            fclose($SongFile);
            echo "Your song has been added to the list.\n";
        }
    }
    
   
    if ((!file_exists("SongOrganizer/songs.txt")) 
    	|| (filesize("SongOrganizer/songs.txt") == 0))
        echo "<p>There are no songs in the list.</p>\n";
    else
    {
        $SongArray = file("SongOrganizer/songs.txt");
        echo "<table border=\"1\" width=\"100%\" 
        	 style=\"background-color:lightgray\">\n";
        foreach ($SongArray as $Song)
        {
            echo "<tr>\n";
            echo "<td>" . htmlentities($Song) . "</td>";
            echo "</tr>\n";
        }
        echo "</table>";
    }
?> 


<!-- Display hyperlinks for the three functions in the switch statement 
	(Sort Ascending, Remove Duplicates, and Shuffle) -->
<p>
    <a href="SongOrganizer.php?action=Sort%20Ascending">Sort Song List</a><br />
    <a href="SongOrganizer.php?action=
    Remove%20Duplicates">Remove Duplicate Songs</a><br />
    <a href="SongOrganizer.php?action=Shuffle">
    Randomize Song List</a><br />
</p>

<!--  web form for entering new song names into the song list: -->

<form action="SongOrganizer.php" method="post">
    <p>Add a New Song</p>
    <p>Song Name: <input type="text" name="SongName" /></p>
    <p><input type="submit" name="submit" value="Add Song to List" />
    <input type="reset" name="reset" value="Reset Song Name" /></p>
</form>

Any help would be appreciated! 

Edited April 12, 2014 by jameshay

[QuickOldCar]

One thing you can do to remove those notices is define the array

 

 

$SongArray = array();

 

You can also check if it's actually an array

 

 

if(is_array($SongArray)){

 

And maybe check your file permissions for SongOrganizer/songs.txt

[boompa]

If you look at the manual page for the file() function, you'll see that it returns FALSE on failure. I suspect that is the case here.

[mac_gyver]

in your posted code, lines 52 to 61 are your form processing logic, and are where the variables/arrays are defined at. however, the code following line 61 is also part of your form processing logic. you need to move the closing } that is on line 61 down so that it is after the end of your form processing logic.