Question Description
Im trying to learn for my Computer Science class and Im stuck. Can you help?
Exercise 6-1
Create a Song Organizer script that stores songs in a text ?le. Include
functionality that allows users to view the song list and prevents the
same song name from being entered twice. Also, include code that
sorts the songs by name, deletes duplicate entries, and randomizes
the song list with the shuf?e() function.
1. Create a new document in your text editor.
2. Type the declaration, element, header
information, and element. Use the strict DTD and
Song Organizer as the content of the element.
3. Add the following XHTML code and script section to the
document body:
Song Organizer
4. Add the following code to the script section to handle any
parameters in the URL:
if (isset($_GET['action'])) {
if ((?le_exists("SongOrganizer/songs.txt"))
&& (?lesize("SongOrganizer/songs.txt")
!= 0)) {
$SongArray = ?le(
"SongOrganizer/songs.txt");
switch ($_GET['action']) {
} // End of the switch statement
}
}
5. Add the following code to the body of the switch statement
to handle the three options (Sort Ascending, Remove
Duplicates, and Shu?e):
case 'Remove Duplicates':
$SongArray = array_unique(
$SongArray);
$SongArray = array_values(
$SongArray);
break;
case 'Sort Ascending':
sort($SongArray);
break;
case 'Shuf?e':
shuf?e($SongArray);
break;
6. Add the following code immediately after the switch state-
ment to save the song list after it has been modi?ed:
if (count($SongArray)>0) {
$NewSongs = implode($SongArray);
$SongStore = fopen(
"SongOrganizer/songs.txt",
"wb");
if ($SongStore === false)
echo "There was an error
updating the song ?len";
else {
fwrite($SongStore, $NewSongs);
fclose($SongStore);
}
}
else
unlink("SongOrganizer/songs.txt");
7. Add the following code to the end of the script section to
handle any data submitted from the Web form:
if (isset($_POST['submit'])) {
$SongToAdd = stripslashes(
$_POST['SongName']) . "n";
$ExistingSongs = array();
if (?le_exists("SongOrganizer/songs.txt")
&& ?lesize("SongOrganizer/songs.txt")
> 0) {
$ExistingSongs = ?le(
"SongOrganizer/songs.txt");
}
}
8. Add the following if statement immediately after the block Although this
where the song ?le data was read into the $ExistingSongs form does not
allow for dupli-
array. This if statement checks to see if the song name
cate entries,
entered is already in the song list, and displays a message if you still need
the song already exists. to be able to remove
if (in_array($SongToAdd, $ExistingSongs)) { them if necessary. There
echo "The song you entered already may be other methods of
exists!n"; adding songs to the list,
echo "Your song was not added to the and the other methods
list."; may allow duplicate
} entries.
9. Add the following else clause to the preceding if statement.
This else clause adds the new song to the song list ?le.
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";
}
}
10. Add the following code to the end of the script section to dis-
play the song list, or a message that there are no songs in the
list if the list is empty:
if ((!?le_exists("SongOrganizer/songs.txt"))
|| (?lesize("SongOrganizer/songs.txt")
== 0))
echo "There are no songs in the
list.n";
else {
$SongArray = ?le(
"SongOrganizer/songs.txt");
echo "n";
foreach ($SongArray as $Song) {
echo "n";
echo "" . htmlentities($Song) .
"";
echo "n";
}
echo "n";
}
11. Add the following XHTML code immediately after the PHP
script section to display hyperlinks for the three functions in
the switch statement (Sort Ascending, Remove Duplicates,
and Shu?e):
Sort Song List
Remove Duplicate Songs
Randomize Song list
12. Next, add the following XHTML code to create a Web form
for entering new song names into the song list:
Add a New Song
Song Name:
13. Save the document as SongOrganizer.php in the Projects
directory for Chapter 6 and upload the ?le to the server.
14. Open the SongOrganizer.php ?le in your Web browser by
entering the following URL: http:///PHP_
Projects/Chapter.06/Projects/SongOrganizer.php.
15. Close your Web browser window.
