strpos() helps to find the position of the first occurrence of a substring in a string.
strpos()
<?php
echo strpos(“Welcome to the php world”,”php”);
?>
Output : 15
PHP Questions and Answers
PHP is an important part of the web world, and every web developer should have the basic knowledge in PHP. Common PHP questions, which should help you become a best PHP developer.
What is sql injection ? Please explain it.
SQL injection is a code injection technique and it is using to attack data driven applications, in which malicious SQL statements are inserted into an entry field for execution (e.g. to dump the database contents to the attacker). SQL injection must exploit a security vulnerability in an application’s software, for example, when user input is either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and unexpectedly executed. SQL injection is mostly known as an attack vector for websites but can be used to attack any type of SQL database.
Please refer this URL : http://en.wikipedia.org/wiki/SQL_injection
How to delete a file from the system using PHP ?
unlink() is using tp delete the given file from the file system.
unlink()
<?php
$fh = fopen(‘page.html’, ‘a’);
fwrite($fh, ‘< h1>Hello world!‘);
fclose($fh);
unlink(‘page.html’);
?>
What is the use of the function htmlentities in PHP ?
It helps to convert all applicable characters to HTML entities.
htmlentities()
<?php
htmlentities($str);
// Outputs: A ‘quote’ is < ;b> ;bold< ;/b> ;
echo htmlentities($str, ENT_QUOTES);
// Outputs: A & #039 ;quote& #039 ; is < ;b> ;bold< ;/b> ; (ENT_QUOTES Will convert both double and single quotes.)
?>
?>
Is it possible to decrypt md5 hashes in PHP ?
MD5 is a hashing algorithm, you can not revert the hash value.
What is the difference between $var and $$var?
In PHP , both are variables. But $var is a variable with a fixed name. $$var is a variable who’s name is stored in $var. For example, if $var contains “user”, $$var is the same as $user.
What is the use of “ksort” in php?
ksort() id using to sort an array by key in reverse order.
ksort()
<?php
$fruits = array(“d”=>”lemon”, “a”=>”orange”, “b”=>”banana”, “c”=>”apple”);
ksort($fruits);
foreach ($fruits as $key => $val) {
echo “$key = $val\n”;
}
?>
Output :
a = orange
b = banana
c = apple
d = lemon
User has defined an array with $arr[0]=0, $arr[1]=1, $arr[2]=2 and $arr[true]=3 then what is the result of $arr[1] ?
Answer : 3
Key value of ‘true’ will act as 1. So it wil replace the array value from 1 to 3