Set - 4

Question 6 :

What's the output of the ucwords function in this example?

$formatted = ucwords("TECHPREPARATIONS IS COLLECTION OF INTERVIEW QUESTIONS");
print $formatted;

What will be printed is TECHPREPARATIONS IS COLLECTION OF INTERVIEW QUESTIONS.

Answer :

ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it's worth using strtolower() first.


Question 7 :

What's the difference between htmlentities() and htmlspecialchars()?

Answer :

htmlspecialchars only takes care of <, >, single quote ', double quote " and ampersand. htmlentities translates all occurrences of character sequences that have different meaning in HTML.


Question 8 :

How can we extract string "abc.com" from a string "mailto:info@abc.com?subject=Feedback" using regular expression of PHP?

Answer :

$text = "mailto:info@abc.com?subject=Feedback";
preg_match('|.*@([^?]*)|', $text, $output);
echo $output[1];

Note that the second index of $output, $output[1], gives the match, not the first one, $output[0].


Question 9 :

So if md5() generates the most secure hash, why would you ever use the less secure crc32() and sha1()?

Answer :

Crypto usage in PHP is simple, but that doesn't mean it's free. First off, depending on the data that you're encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down, if frequent md5() generation is required.


Question 10 :

How can we destroy the session, how can we unset the variable of a session?

Answer :

session_unregister() - Unregister a global variable from the current session
session_unset() - Free all session variables