I'm getting the following error with $_POST['str']:
Notice: Undefined index: str in C:\Program Files\EasyPHP-5.3.8.0\www\strrev.php on line 12
I spent too much time to find an answer for this but no luck! Please take a look at the code and let me know what's wrong with it?
<html>
<head>
<title></title>
</head>
<body>
<?php
if (trim($_POST['str'])) {
$str = $_POST['str'];
$len = strlen($str);
for($i=($len-1); $i>=0;$i--) {
echo $str[$i];
}
} else {
?>
<form method="post" action="">
<input type="text" name="str" />
<input type="button" name="submit" value="Reverse" />
</form>
<?php
}
?>
</body>
</html>
It shows the text field and Reverse button beside the error. And also when I push the button nothing will happens.
Change if (trim($_POST['str'])) to if (!empty($_POST['str']))
Your if statement is trying to trim an array index that does not exist, hence the error. You must check if your index exists first.
In case anyone is wondering - I used empty instead of isset as the OP, by using trim, implied (or at least, I inferred from this) that a properly set $_POST['str'] containing an empty string was unacceptable. This won't fix the case where $_POST['str'] contains a bunch of spaces, however.
You're not checking if a POST has actually occured:
<html>
...
<?php
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
if ($_POST yada yada yada) {
...
}
}
?>
<form action="" method="POST">
...
</form>
...
</html>
$str is not necessarily an array. In order to loop through it, it needs to be an array. It's just copying that value from $_POST['str'], so when you do the post either
Make sure it's an array with
if (is_array($str))