PHP interview questions (classic)

Through my experience and the collection of some information on the Internet, I have compiled some interview questions in the PHP workplace. I hope it will be helpful to everyone in the future.

1. What is the difference between the get and post submission methods in the form?

Answer: Get is a request sent by HTTP protocol and received through url parameters, while post is entity data, which can submit a large amount of information through a form.

2. What is the difference between session and cookie?

Answer: session: A global unique variable that stores user access, stored in the (session_dir) location in the directory specified by PHP on the server

Cookie: Used to store the data when continuously accessing a page Used, it is stored on the client side. For cookies, it is stored in the Temp directory of the user's WIN.

Both can set the length of time through time

3. What is the transaction in the database?

Answer: Transaction is An ordered set of database operations as a unit. A transaction is considered successful if all operations in the group succeed, even if only one operation fails, the transaction is not successful. If all operations are completed, the transaction is committed and its modifications are applied to all other database processes. If an operation fails, the transaction is rolled back and the effects of all operations in the transaction are canceled.

4. Use PHP to print out the time of the previous day in the format of 2006-5-10 22:21:21

Answer: echo date('Y-m-d H:i: s', strtotime('-1 days'));

5. The difference between echo(), print(), and print_r()

Answer: echo is PHP statements, print and print_r are functions. Statements have no return value, and functions can have return values ​​(even if they are useless)

print() can only print out the values ​​of simple type variables (such as int, string)

print_r() can print out the value of complex type variables (such as arrays, objects)

echo Output one or more strings

6. Can make HTML and Templates used separately from PHP

Answer: Smarty, Dwoo, TinyButStrong, Template Lite, Savant, phemplate, XTemplate

10. The meaning of PHP

Answer: PHP is a scripting language based on the server to create dynamic websites. You can use PHP and HTML to generate the website homepage

11. What is the function of MYSQL to obtain the current time?, format The function to convert date is

Answer: now(), date()

12. Check whether a variable Is there a set function? Is it an empty function?

Answer:isset($str),empty($str);

13. Obtain query results What is the function of the total number of sets?

Answer: mysql_num_rows($result);

14. $arr = array('james', 'tom', 'symfony' ); Please print out the value of the first element

Answer: echo $array[0];

15. Please use ' ,' separated by characters and combined into string output

Answer: for($i=0;$i

16. $a = 'abcdef'; Please take out the value of $a and print out the first letter

Answer:echo $a{ 0} or echo substr($a,0,1)

17. Can PHP be connected to databases such as sql server/oracle?

Answer: Of course

18. Please write the PHP5 permission control modifier

Answer: public (public), private (private), protected (inherited)

19. Please write down the constructor and destructor of php5

Answer: __construct , __destruct

20. What tools are used for version control?

CVS and SVN, SVN is known as the next generation of CVS and has powerful functions, but CVS is an old brand with a high market share. I have always used SVN, and the question is what tool should I use? Well, this may be necessary Answer like this: CVS Server on Apache as the server, WinCVS as the client; Subversion on Apache/DAV as the server, TortoiseSVN as the client, or Subclipse as the client

21. In HTTP 1.0, the meaning of status code 401 is ____; if the prompt "File not found" is returned, the header function can be used, and its statement is ____.

Answer: 401 means unauthorized; header("HTTP/1.0 404 Not Found");[See Reference Manual》Function Reference》HTTP Function》header]

22. The function of array function arsort is ____; the function of statement error_reporting(2047) is ____.

Answer: arsort: reverse sort the array and maintain the index relationship. The function of error_reporting(2047) is: report All errors and warnings

23. Write a regular expression Expression, filter all JS/VBS scripts on the web page (that is, remove the script tag and its content):

<?php
$script="以下内容不显示：<script language=&#39;javascript&#39;>alert(&#39;cc&#39;);</script>";
echo preg_replace("/<script[^>].*?>.*?</script>/si", "替换内容", $script);
?>

24 The statements include and require can both include another file into the current file. The difference between them is ____; in order to avoid including the same file multiple times, you can use the statement ____ instead.

Answer: When handling failure, include() generates a warning and require() causes a fatal error; require_once()/include_once();

25. The following code will What is produced? Why?

$num =10;

function multiply(){

$num =$num *10;

}

multiply();

echo $num;

Because the function multiply() does not specify $num as a global variable (such as global $num or $_GLOBALS['num'] ), so the value of $num is 10.

The above are the interview questions I compiled online. I hope they will be helpful to everyone in the future.

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