php answer

46) What is the difference between the functions unlink and unset?
unlink is a function for file system handling. It will simply delete the file in context. unset will set UNSET the
specified variable.
unlink is used to delete a file. unset is used to destroy an earlier declared variable.
47) What are the different types of errors in PHP?
1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script – for example,
accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all
– although you can change this default behavior.
2. Warnings: These are more serious errors – for example, attempting to include() a file which does not exist.
By default, these errors are displayed to the user, but they do not result in script termination.
3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling
a non-existent function. These errors cause the immediate termination of the script, and PHP’s default
behavior is to display them to the user when they take place.
48) How can we create a session variable & terminate it?
$_SESSION[’name’] = “Chinmay”;
To destroy a session: unset($_SESSION[’name’]);
49) How to Create a Cookie & destroy it in PHP?
variable – name of the cookie variable
variable – value of the cookie variable
time – expiry time
Example: setcookie(”test”,$i,time()+3600);
Test – cookie variable name
$i – value of the variable ‘Test’
time()+3600 – denotes that the cookie will expire after an one hour.
Destroy a cookie by specifying expiry time
Example: setcookie(”test”,$i,time()-3600); // already expired time
Reset a cookie by specifying its name only
50) What is the difference between sizeof($array) and count($array)?
sizeof($array) – This function is an alias of count()
count($array) – If you just pass a simple variable instead of an array it will return 1.


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