Two sets of PHP interview questions (useful for interviews)_PHP tutorial

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

Answer: get is to send a request through the HTTP protocol and receive it through url parameters, while post is entity data and can submit a large amount of information through a form.

2. What is the difference between session and cookie?

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

Cookie: Used to store consecutive visits to a page. It is stored on the client. 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 are transactions in the database?

Answer: A 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 will affect all other database processes. If an operation fails, the transaction is rolled back and the effects of all operations in the transaction are canceled.

Brief question:

1. Use PHP to print out the time of the previous day in the format of 2006-5-10 22:21:21 (2 points)

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

2. The difference between echo(), print() and print_r() (3 points)

Answer: echo is a PHP statement, 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 value 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

3. A template that allows HTML and PHP to be used separately (1 point)

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

5. What tools are used for version control? (1 point)

Answer: cvs, svn, vss;

6. How to implement string flipping? (3 points)

Answer: echo strrev($a);

7. Methods to optimize MYSQL database. (4 points, write more and get more)

Answer:

1. Select the most applicable field attribute, reduce the length of the defined field as much as possible, and try to set the field to NOT NULL, such as 'province, gender', it is best to set it to ENUM

2. Use connection (JOIN) instead of subquery:

a. Delete customers without any orders: DELETE FROM customerinfo WHERE customerid NOT in (SELECT customerid FROM orderinfo)

b. Extract all customers without orders: SELECT FROM customerinfo WHERE customerid NOT in (SELECT customerid FROM orderinfo)

c. Improve b’s speed optimization: SELECT FROM customerinfo LEFT JOIN orderid customerinfo.customerid=orderinfo.customerid

WHERE orderinfo.customerid IS NULL

3. Use UNION to replace manually created temporary tables

a. Create a temporary table: SELECT name FROM `nametest` UNION SELECT username FROM `nametest2`

4. Transaction processing:

a. Ensure data integrity, such as adding and modifying at the same time. If both are true, both will be executed. If one fails, it will fail.

mysql_query("BEGIN");

mysql_query("INSERT INTO customerinfo (name) VALUES ('$name1')";

mysql_query("SELECT * FROM `orderinfo` where customerid=".$id");

mysql_query("COMMIT");

5. Lock the table and optimize transaction processing:

a. We use a SELECT statement to retrieve the initial data, and through some calculations, use an UPDATE statement to update the new values ​​into the table.

A LOCK TABLE statement containing the WRITE keyword ensures that

There will be no other access to insert, update or delete inventory

mysql_query("LOCK TABLE customerinfo READ, orderinfo WRITE");

mysql_query("SELECT customerid FROM `customerinfo` where id=".$id);

mysql_query("UPDATE `orderinfo` SET ordertitle='$title' where customerid=".$id);

mysql_query("UNLOCK TABLES");

6. Use foreign keys to optimize lock tables

a. Map the customerid in customerinfo to the customerid in orderinfo,

Any record without a legal customerid will not be written to orderinfo

CREATE TABLE customerinfo

(

customerid INT NOT NULL,

PRIMARY KEY(customerid)

)TYPE = INNODB;

CREATE TABLE orderinfo

(

orderid INT NOT NULL,

customerid INT NOT NULL,

PRIMARY KEY(customerid,orderid),

FOREIGN KEY (customerid) REFERENCES customerinfo

(customerid) ON DELETE CASCADE

)TYPE = INNODB;

Note: 'ON DELETE CASCADE', this parameter ensures that when a record in the customerinfo table is deleted, the order will also be deleted

All records of the user in the table. Note that when using foreign keys, the transaction security type must be defined as INNODB;

7. Create index:

a. Format:

(Normal index)->

Create: CREATE INDEX ON tablename (index field)

Modification: ALTER TABLE tablename ADD INDEX [index name] (index field)

Create a table with a specified index: CREATE TABLE tablename([...],INDEX[index name](index field))

(unique index)->

Create: CREATE UNIQUE ON tablename (index field)

Modification: ALTER TABLE tablename ADD UNIQUE [index name] (index field)

Create a table with a specified index: CREATE TABLE tablename([...],UNIQUE[index name](index field))

(primary key)->

It is a unique index, which is usually created when creating a table. The format is:

CREATA TABLE tablename ([...],PRIMARY KEY[index field])

8. Optimize query statements

a. It is best to perform comparison operations on the same fields and minimize function operations on the established index fields

Example 1:

SELECT * FROM order WHERE YEAR(orderDate)<2008;(Slow)

SELECT * FROM order WHERE orderDate<"2008-01-01";(Quick)

Example 2:

SELECT * FROM order WHERE addtime/7<24;(Slow)

SELECT * FROM order WHERE addtime<24*7;(fast)

Example 3:

SELECT * FROM order WHERE title like "%good%";

SELECT * FROM order WHERE title>="good" and name<"good";

8. What does PHP mean (get 1 point)

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

9. What is the function of MYSQL to obtain the current time?, and the function of formatting date is (2 points)

Answer: now(), date()

10. A method to intercept Chinese text strings without garbled characters. (3 points)

Answer: function GBsubstr($string, $start, $length) {

if(strlen($string)>$length){

$str=null;

$len=$start+$length;

for($i=$start;$i<$len;$i++){

if(ord(substr($string,$i,1))>0xa0){

$str.=substr($string,$i,2);

$i++;

}else{

$str.=substr($string,$i,1);

}

}

return $str.'...';

}else{

return $string;

}

}

11. Have you ever used version control software? If so, what is the name of the version control software you used? (1 point)

12. Have you ever used a template engine? If so, what is the name of the template engine you used? (1 point)

Answer: Used, smarty

13. Please briefly describe your most proud development work (4 points)

Answer: Information classification

14. For websites with large traffic, what methods do you use to solve the traffic problem? (4 points)

Answer: Confirm whether the server hardware is sufficient to support the current traffic, separate database reading and writing, and optimize the data table,

Program function rules prohibit external hot links, control the download of large files, and use different hosts to divert main traffic

15. Use PHP to write the code to display the client IP and server IP 1 point)

Answer: Print client IP: echo $_SERVER[‘REMOTE_ADDR’]; or: getenv(‘REMOTE_ADDR’);

Print server IP:echo gethostbyname("www.bolaiwu.com")

16. What is the difference between the include and require statements? To avoid including the same file multiple times, you can replace them with (?) statements? (2 points)

Answer: require->require is an unconditional inclusion, that is, if require is added to a process, require will be executed first regardless of whether the condition is true or not

include->include has a return value, but require does not (maybe because require is faster than include)

Note: require is fatal when the included file does not exist or has a syntax error, and include is not

17. How to modify the survival time of SESSION (1 minute).

Answer: Method 1: Set session.gc_maxlifetime in php.ini to 9999 and restart apache

Method 2:$savePath = "./session_save_dir/";

$lifeTime = hours * seconds;

session_save_path($savePath);

session_set_cookie_params($lifeTime);

session_start();

Method 3: setcookie() and session_set_cookie_params($lifeTime);

18. There is a web page address, such as the homepage of the PHP Development Resource Network: http://www.phpres.com/index.html, how to get its content? ($1 point)

Answer: Method 1 (for PHP5 and above):

$readcontents = fopen("http://www.phpres.com/index.html", "rb");

$contents = stream_get_contents($readcontents);

fclose($readcontents);

echo $contents;

Method 2:

echo file_get_contents("http://www.phpres.com/index.html");

19. 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 (?); (2 points)

Answer: Status 401 means not authorized, header("Location:www.xxx.php");

12. In PHP, heredoc is a special string, and its end mark must be? (1 point)

Answer: The syntax of heredoc is to use "<<<" plus self-defined paired tags, and the text within the tag range is regarded as a string

Example:

$str = <<

my name is Jiang Qihui!

SHOW;

13. Talk about the advantages and disadvantages of asp, php and jsp (1 point)

Answer: ASP’s full name is Active Server Pages, which is a WEB server-side development environment that can be used to generate and operate

Run dynamic, interactive, high-performance WEB service applications. ASP uses the scripting language VB Script (Java script

) as its own development language.

PHP is a cross-platform server-side embedded scripting language. It borrows a lot of syntax from C, Java and Perl languages ​​

, and coupled with PHP's own features, allowing WEB developers to quickly write dynamically generated pages. It supports most of the current

Database. Another point is that PHP is completely free. You don’t need to spend money. You can download it from the PHP official site (http://www.php.ne

t) Free download. And you have unrestricted access to the source code, and you can even add the features you need.

JSP is a new generation website development language launched by Sun. It completely solves a common problem of ASP and PHP currently -

Script-level execution (it is said that PHP4 has also been compiled and run with the support of Zend). Sun uses its own expertise in Jav

The extraordinary achievements in a have made Java a new fruit in addition to Java applications and Java Applets, which is Js

p——Java Server Page. Jsp can complete a powerful website with the support of Serverlet and JavaBean

Program.

All three provide the ability to mix certain program code in HTML code and have the language engine interpret and execute the program code.

But the JSP code is compiled into Servlet and interpreted and executed by the Java virtual machine. This compilation operation is only performed on the JSP page

Occurs on first request. In ASP, PHP, and JSP environments, HTML code is mainly responsible for describing the display style of information

, and program code is used to describe the processing logic. Ordinary HTML pages only rely on the web server, while ASP and PH

P. JSP pages require additional language engines to analyze and execute program code. The execution results of the program code are re-embedded into

HTML code, and then sent to the browser together. ASP, PHP, and JSP are all web server-oriented technologies

, the client browser does not require any additional software support.

14. Talk about your understanding of mvc (1 point)

Answer: An application completed by model, view, and controller

The model sends the functions to be implemented to the controller, and the controller receives the organized functions and passes them to the view;

15. Write the SQL of the names of the ten people with the most posts, using the following table: members (id, username, posts, pass, email) (2 points)

Answer: SELECT * FROM `members` ORDER BY posts DESC limit 0,10;

16. Please explain the difference between passing by value and passing by reference in PHP. When to pass by value and when to pass by reference? (2 points)

Answer: Pass by value: Any changes to the value within the function scope will be ignored outside the function

Pass by reference: Any changes to the value within the scope of the function will also reflect these modifications outside the function

Advantages and Disadvantages: When passing by value, PHP must copy the value. Especially for large strings and objects, this can be a costly operation.

Passing by reference does not require copying the value, which is very good for improving performance.

17. What is the function of error_reporting in PHP? (1 point)

Answer: Set error level and error message reporting

18. Please write a function to verify whether the format of the email is correct (2 points)

Answer: function checkEmail($email)

{

$pregEmail = "/([a-z0-9]*[-_/.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[ a-z0-9]+)+[/.][a-z]{2,3}([/.][a-z]{2})?/i";

return preg_match($pregEmail,$email);

}

19. Briefly describe how to get the current execution script path, including the obtained parameters. (2 points)

Answer:$script_name = basename(__file__); print_r($script_name);

21. What is the function to pop up a dialog box in a JS form? What is the function to get input focus? (2 points)

Answer: Pop-up dialog box: alert(), prompt(), confirm()

Get input focus focus()

22. What is the redirect function of JS? How to introduce an external JS file? (2 points)

Answer: window.location.href,

23. What is the difference between foo() and @foo()? (1 point)

Answer: @foo() controls error output

24. How to declare a class named "myclass" without methods and attributes? (1 point)

Answer: class myclass{ }

25. How to instantiate an object named "myclass"? (1 point)

Answer: new myclass()

26. How do you access and set the attributes of a class? (2 points)

Answer:$object = new myclass();

$newstr = $object->test;

$object->test = "info";

27. What is the difference between mysql_fetch_row() and mysql_fetch_array? (1 point)

Answer: mysql_fetch_row is to take out an array of 1 row from the result set as an enumeration

mysql_fetch_array is to take out a row array from the result set as an associative array, or a numeric array, both

28. What is the GD library used for? (1 point)

Answer: The gd library provides a series of APIs for processing images. You can use the GD library to process images or generate images.

On websites, the GD library is usually used to generate thumbnails or add watermarks to images or generate reports on website data.

29. Point out some ways to enter a piece of HTML code in PHP. (1 point)

Answer:echo "aaa";

30. Which of the following functions can open a file to read and write the file? (1 point)

(a) fget() (b) file_open() (c) fopen() (d) open_file() [ c ]

31. Which of the following options does not add john to the users array? (1 point)

　(a) $users[] = ‘john’;

　(b) array_add($users,’john’);

　(c) array_push($users,‘john’);

　(d) $users ||= ‘john’; [ a , c ]

32. Will the following program be input? (1 point)

　$num = 10;

Function multiply(){

　$num = $num * 10;

　}

multiply();

echo $num;

　?>

Output: 10

33. Use PHP to write a simple query to find out all the content named "Zhang San" and print it out (2 points)

Table name User

　Name Tel Content Date

Zhang San 13333663366 Graduated from college 2006-10-11

Zhang San 13612312331 Bachelor’s degree 2006-10-15

Zhang Si 021-55665566 Graduated from technical secondary school 2006-10-15

Please complete the code according to the above question:

$mysql_db=mysql_connect("local","root","pass");

@mysql_select_db("DB",$mysql_db);

$result = mysql_query("SELECT * FROM `user` WHERE name='Zhang San'");

while($rs = mysql_fetch_array($result)){

echo $rs["tel"].$rs["content"].$rs["date"];

}

34. How to use the following classes and explain what they mean? (3)

class test{

function Get_test($num){

　 $num=md5(md5($num)."En");

Return $num;

　 }

　}

Answer:$testnum = "123";

$object = new test();

$encrypt = $object->Get_test($testnum);

echo $encrypt;

The class test contains the Get_test method, and the instantiated class calls the method multi-string encryption

35. Write the format of SQL statements: insert, update, delete (4 points)

Table name User

　Name Tel Content Date

Zhang San 13333663366 Graduated from college 2006-10-11

Zhang San 13612312331 Bachelor’s degree 2006-10-15

Zhang Si 021-55665566 Graduated from technical secondary school 2006-10-15

(a) There is a new record (Xiao Wang 13254748547 graduated from high school 2007-05-06). Please use SQL statements to add it to the table

mysql_query("INSERT INTO `user` (name,tel,content,date) VALUES

('Xiao Wang','13254748547','High School Graduation','2007-05-06')")

(b) Please use sql statement to update Zhang San’s time to the current system time

$nowDate = date("Ymd");

mysql_query("UPDATE `user` SET date='".$nowDate."' WHERE name='Zhang Shan'");

(c) Please write to delete all records named Zhang Si

mysql_query("DELETE FROM `user` WHERE name='Zhang Si'");

36. Please write the meaning of data type (int char varchar datetime text); what is the difference between varchar and char (2 points)

Answer: int is a numeric type, char fixed length string, varchar actual length string, datetime date and time type, text text string

The field of char is fixed to the length set by the created table, and varchar is a variable-length character

38. Write the output result of the following program (1 point)

　$b=201;

　$c=40;

$a=$b>$c?4:5;

echo $a;

　?>

Answer: 4

39. Is there a function that detects whether a variable is set? What is the function that detects whether it is empty? (2 points)

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

40. What is the function to obtain the total number of query result sets? (1 point)

Answer: mysql_num_rows($result);

41. $arr = array('james', 'tom', 'symfony'); Please print out the value of the first element (1 point)

Answer: echo $array[0];

42. Please separate the array values ​​in question 41 with ',' signs and merge them into string output (1 point)

Answer: for($i=0;$i

43. $a = 'abcdef'; Please take out the value of $a and print out the first letter (1 point)

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

44. Can PHP be connected to databases such as sql server/oracle? (1 point)

Answer: Of course

45. Please write the PHP5 permission control modifier (3 points)

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

46. Please write the constructor and destructor of php5 (2 points)

Answer: __construct , __destruct

47. Complete the following:

(1) Create a news release system with the table name message and the following fields (3 points)

　id article id

Title Article title

content article content

category_id article category id

hits Click count

Answer:CREATE TABLE 'message'(

'id' int(10) NOT NULL auto_increment,

'title' varchar(200) default NULL,

'content' text,

'category_id' int(10) NOT NULL,

'hits' int(20),

PRIMARY KEY('id');

)ENGINE=InnoDB DEFAULT CHARSET=utf8;

(2) The same news release system as above: the comment table records the content of user replies, and the fields are as follows (4 points)

Comment_id reply id

id article id, associated with the id in the message table

comment_content reply content

Now you need to query the database to get a list of article titles in the following format, and sort them by the number of replies, with the highest reply at the top

Article id Article title Number of clicks Number of replies

Use a SQL statement to complete the above query. If the article has no replies, the number of replies will be displayed as 0

Answer: SELECT message.id id,message.title title,IF(message.`hits` IS NULL,0,message.`hits`) hits,

IF(comment.`id` is NULL,0,count(*)) number FROM message LEFT JOIN

comment ON message.id=comment.id GROUP BY message.`id`;

(3) In the above content management system, the category table stores classification information, and the fields are as follows (3 points)

category_id int(4) not null auto_increment;

categroy_name varchar(40) not null;

When the user enters an article, select the article category by selecting the drop-down menu

Write how to implement this drop-down menu

Answer: function categoryList()

{

$result=mysql_query("select category_id,categroy_name from category")

          or die("Invalid query: " . mysql_error());

print("/n");

while($rowArray=mysql_fetch_array($result))

{

print("".$rowArray['categroy_name']."/n");

}

print("

");

}

Programming questions:

1. Write a function to retrieve the file extension from a standard URL as efficiently as possible

For example: http://www.sina.com.cn/abc/de/fg.php?id=1 You need to remove php or .php

Answer 1:

function getExt($url){

$arr = parse_url($url);

$file = basename($arr['path']);

$ext = explode(".",$file);

return $ext[1];

}

Answer 2:

function getExt($url) {

$url = basename($url);

$pos1 = strpos($url,".");

$pos2 = strpos($url,"?");

if(strstr($url,"?")){

return substr($url,$pos1 + 1,$pos2 - $pos1 - 1);

} else {

return substr($url,$pos1);

}

}

2. In HTML language, the meta tag in the header of the page can be used to output the encoding format of the file. The following is a standard meta statement

Please use PHP language to write a function to change the charset part value in a similar meta tag in a standard HTML page to big5

Please note:

　1. Need to process the complete html page, that is, not just this meta statement

2. Ignore case

3. ' and " are interchangeable here

4. The quotation marks on both sides of 'Content-Type' can be ignored, but the quotation marks on both sides of 'text/html; charset=gbk' are not allowed

5. Pay attention to excess spaces

3. Write a function to calculate the relative paths of two files

For example $a = '/a/b/c/d/e.php';

$b = '/a/b/12/34/c.php';

Calculate that the relative path of $b relative to $a should be ../../c/d and add () to

Answer: function getRelativePath($a, $b) {

$returnPath = array(dirname($b));

$arrA = explode('/', $a);

$arrB = explode('/', $returnPath[0]);

for ($n = 1, $len = count($arrB); $n < $len; $n++) {

if ($arrA[$n] != $arrB[$n]) {

break;

} }

}

if ($len - $n > 0) {

$returnPath = array_merge($returnPath, array_fill(1, $len - $n, '..'));

}

$returnPath = array_merge($returnPath, array_slice($arrA, $n));

return implode('/', $returnPath);

}

echo getRelativePath($a, $b);

Fill in the blanks:

1. In PHP, the name of the current script (excluding path and query string) is recorded in the predefined variable __$_SERVER['PHP_SELF']__; and the URL linking to the current page is recorded in the predefined variable __$_SERVER['PHP_SELF']__ Define variable __$_SERVER['HTTP_REFERER']__

中

2. Execute the program segment will output __0__.

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

4. The function of the array function arsort is to __reverse sort the array and maintain the index relationship__; the function of the statement error_reporting(2047) is to __report all errors and warnings__.

5.The database connection string format in PEAR is____.

6. Write a regular expression to filter all JS/VBS scripts on the web page (that is, remove the scrīpt tag and its content): preg_replace("/].*?> .*?/si", "newinfo", $script);

7. Install PHP as an Apache module. In the file http.conf, first use the statement ____ to dynamically load the PHP module, and then use the statement ____ to make Apache treat all files with the extension php as PHP script processing.

LoadModule php5_module "c:/php/php5apache2.dll" , AddType application/x-httpd-php .php,

8. The statements include and require can include another file into the current file. The difference between them is ____; in order to avoid including the same file multiple times, you can replace them with the statement __require_once||include_once__.

9. The attributes of a class can be serialized and saved to the session, so that the entire class can be restored later. The function used for this is ____.

10. The parameter of a function cannot be a reference to a variable, unless __allow_call_time_pass_reference boolean__ is set to on in php.ini.

11. The meaning of LEFT JOIN in SQL is __natural left outer link__. If tbl_user records the student's name and student ID, tbl_score records the student's student ID (some students were expelled after the exam and there is no record of them)

And test scores (score) and test subjects (subject), if you want to print out the names of each student and the corresponding total score of each subject, you can use the SQL statement ____.

12. In PHP, heredoc is a special string, and its end mark must be____.

Programming questions:

13. Write a function that can traverse all files and subfolders in a folder.

Answer:

function my_scandir($dir)

{

$files = array();

if ( $handle = opendir($dir) ) {

while ( ($file = readdir($handle)) !== false ) {

            if ( $file != ".." && $file != "." ) {

                if ( is_dir($dir . "/" . $file) ) {

                                                                                                  $files[$file] = scandir($dir . "/" . $file);

        }else {

$files[] = $file;

        }

      }

} }

closedir($handle);

return $files;

}

}

14. Briefly describe the implementation principle of infinite classification in the forum.

Answer:

/*

The data table structure is as follows:

CREATE TABLE `category` (

`categoryID` smallint(5) unsigned NOT NULL auto_increment,

`categoryParentID` smallint(5) unsigned NOT NULL default '0',

`categoryName` varchar(50) NOT NULL default '',

PRIMARY KEY (`categoryID`)

) ENGINE=MyISAM DEFAULT CHARSET=gbk;

INSERT INTO `category` ( `categoryParentID`, `categoryName`) VALUES

(0, 'First level category'),

(1, 'Second level category'),

(1, 'Second level category'),

(1, 'Second level category'),

(2, 'Third level category'),

(2, '333332'),

(2, '234234'),

(3, 'aqqqqqd'),

(4, 'Haha'),

(5, '66333666');

*/

//Specify the category id variable $category_id, and then return all subcategories of the category

//$default_category is the default selected category

function Get_Category($category_id = 0,$level = 0, $default_category = 0)

{

global $DB;

$sql = "SELECT * FROM category ORDER BY categoryID DESC";

$result = $DB->query( $sql );

while ($rows = $DB->fetch_array($result))

{

$category_array[$rows[categoryParentID]][$rows[categoryID]] = array('id' => $rows[categoryID], 'parent' => $rows[categoryParentID], 'name' = > $rows

[categoryName]);

}

if (!isset($category_array[$category_id]))

{

return "";

}

foreach($category_array[$category_id] AS $key => $category)

{

if ($category['id'] == $default_category)

{

echo "

}else

{

echo "

}

if ($level > 0)

{

echo ">" . str_repeat( " ", $level ) . " " . $category['name'] . "/n";

}

else

{

echo ">" . $category['name'] . "/n";

}

Get_Category($key, $level + 1, $default_category);

}

unset($category_array[$category_id]);

}

/*

The array format returned by the function is as follows:

Array

(

[1] => Array ( [id] => 1 [name] => First level category [level] => 0 [ParentID] => 0 )

[4] => Array ( [id] => 4 [name] => Secondary category [level] => 1 [ParentID] => 1 )

[9] => Array ( [id] => 9 [name] => Haha [level] => 2 [ParentID] => 4 )

[3] => Array ( [id] => 3 [name] => Secondary category [level] => 1 [ParentID] => 1 )

[8] => Array ( [id] => 8 [name] => aqqqqqd [level] => 2 [ParentID] => 3 )

[2] => Array ( [id] => 2 [name] => Secondary category [level] => 1 [ParentID] => 1 )

[7] => Array ( [id] => 7 [name] => 234234 [level] => 2 [ParentID] => 2 )

[6] => Array ( [id] => 6 [name] => 333332 [level] => 2 [ParentID] => 2 )

[5] => Array ( [id] => 5 [name] => Three-level category [level] => 2 [ParentID] => 2 )

[10] => Array ( [id] => 10 [name] => 66333666 [level] => 3 [ParentID] => 5 )

)

*/

//Specify the category id, and then return the array

function Category_array($category_id = 0,$level=0)

{

global $DB;

$sql = "SELECT * FROM category ORDER BY categoryID DESC";

$result = $DB->query($sql);

while ($rows = $DB->fetch_array($result))

{

$category_array[$rows['categoryParentID']][$rows['categoryID']] = $rows;

}

foreach ($category_array AS $key=>$val)

{

if ($key == $category_id)

{

foreach ($val AS $k=> $v)

{

$options[$k] =

array(

'id' => $v['categoryID'], 'name' => $v['categoryName'], 'level' => $level, 'ParentID'=>$v[' categoryParentID']

);

$children = Category_array($k, $level+1);

if (count($children) > 0)

{

$options = $options + $children;

}

}

}

}

unset($category_array[$category_id]);

return $options;

}

?>

class cate

{

function Get_Category($category_id = 0,$level = 0, $default_category = 0)

{

echo $category_id;

$arr = array(

              '0' => array(

'1' = & gt; Array ('ID' = & gt; 1, 'Parent' = & gt; 0, 'name' = & gt; '1111'),

'2' = & gt; Array ('ID' = & gt; 2, 'Parent' = & gt; 0, 'name' = & gt; '2222'),

'4' = & gt; Array ('ID' = & gt; 4, 'Parent' = & gt; 0, 'name' = & gt; '4444')

                  ),

                                                                         

'3' = & gt; Array ('ID' = & gt; 3, 'Parent' = & gt; 1, 'name' = & gt; '333333'),

>

                            ),

                          

              '3' => array(

                            '6' => array('id' => 6, 'parent' => 3, 'name' => '66666'),

                            '7' => array('id' => 7, 'parent' => 3, 'name' => '77777')

                            ),

              '4' => array(

                            '8' => array('id' => 8, 'parent' => 4, 'name' => '8888'),

                            '9' => array('id' => 9, 'parent' => 4, 'name' => '9999')

                            )    

             );

             if (!isset($arr[$category_id]))

             {

                return "";

             }

    

             foreach($arr[$category_id] AS $key => $cate)

             {

                 if ($cate['id'] == $default_category)

                 {

                     $txt = "

                 }else{

                     $txt = "

                 }

            

                 if ($level > 0)

                 {

                    $txt1 = ">" . str_repeat( "-", $level ) . " " . $cate['name'] . "/n";

                 }else{

                     $txt1 = ">" . $cate['name'] . "/n";

                 }

                 $val = $txt.$txt1;

                 echo $val;

                 self::Get_Category($key, $level + 1, $default_category);

             }

            

        }

        

        

        function getFlush($category_id = 0,$level = 0, $default_category = 0)

        {

            

            ob_start();

            self::Get_Category($category_id ,$level, $default_category);

            $out = ob_get_contents();

            ob_end_clean();

            return $out;

        }    

}

$id =$_GET['id'];

echo "";

$c = new cate();

//$c->Get_Category();

$ttt= $c->getFlush($id,'0','3');

echo $ttt;

echo "

";

?>

1.Which of the following sentences will not add John to the users array?

$users[] = ‘john’;

Successfully added John to the users array.

array_add($users,’john’);

Function array_add() has no definition.

array_push($users,‘john’);

Successfully added John to the users array.

$users ||= ‘john’;

Syntax error.

2. What are the differences between sort(), assort(), and ksort()? Under what circumstances are they used?

sort()

Sort in English alphabetical order according to the value of the elements in the array, and the index keys will be renumbered from 0 to n-1. Mainly used to sort the array when the value of the array index key is irrelevant.

assort()

PHP does not have assort() function, so it may be a typo in asort().

asort()

Like sort(), the elements of the array are arranged in English alphabetical order. The difference is that all index keys are retained, which is especially suitable for sorting associative arrays.

ksort()

Sort in English alphabetical order according to the value of the index key in the array. It is especially suitable for associative arrays that want to sort the index keys.

3. What will the following code produce? Why?

$num =10;

function multiply(){

$num =$num *10;

}

multiply();

echo $num;

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

4. What is the difference between a reference and a regular variable? How to pass by reference? Under what circumstances do we need to do this?

Reference transfers the address of the variable rather than its value, so when the value of a variable is changed in a function, the entire application sees the new value of the variable.

What a regular variable passes to a function is its value. When the function changes the value of this variable, only this function sees the new value, and other parts of the application still see the old value.

$myVariable = “its’ value”;Myfunction(&$myVariable); // Pass parameters as reference

By passing parameters to the function by reference, the variables changed by the function can still retain the new value even after the function ends.

5. What functions can be used to insert function libraries into the currently executing script?

Different understandings of this question will lead to different answers. My first idea is to insert the PHP function library, which is nothing more than include(), include_once(), require(), require_once(), but be careful. Think about it, "function library" should also include com objects and .net function libraries, so our answer should also include com_load and dotnet_load respectively. Next time someone mentions "function library", don't forget these two functions. .

6. What is the difference between foo() and @foo()?

foo() will execute this function, and any interpretation errors, syntax errors, and execution errors will be displayed on the page.

@foo() will hide all the above error messages when executing this function.

Many applications use @mysql_connect() and @mysql_query to hide mysql error messages. I think this is a serious mistake because errors should not be hidden. You must handle them properly and resolve them if possible.

7. How do you debug PHP applications?

I don’t do this very often, I’ve tried a lot of different debugging tools and setting them up on a Linux system is not easy at all. But below I will introduce a debugging tool that has attracted much attention recently.

PHP – Advanced PHP Debugger or PHP – APD, the first step is to execute the following command to install:

After pear install apd is installed, add the following statement at the beginning of your script to start debugging:

apd_set_pprof_trace(); After execution, open the following file to view the execution log:

apd.dumpdir

You can also use pprofp to format the log.

For detailed information, please refer to http://us.php.net/manual/en/ref.apd.php.

8.What is “===”? Give an example where "==" is true but "===" is false.

"===" is for a function that can either return a Boolean value "false" or a function that is not a Boolean value but can be assigned a "false" value. strpos() and strrpos() are Two examples.

The second part of the question is a bit difficult. It is easy to think of an example where "==" is false, but "===" is true, but there are very few examples of the opposite. But I finally found the following example:

if (strpos("abc", "a") == true){ // This part will never be executed, because the position of "a" is 0, converted to Boolean value "false"}if (strpos ("abc", "a") === true){ // This part will be executed because "===" ensures that the value returned by the function strpos() will not be converted into a Boolean value.}

9. How would you define a class myclass with no member functions or attributes?

class myclass{}

10. How do you generate an object of myclass?

$obj = new myclass();

11. How to access the properties of this category and change its value within a category?

Use statement: $this->propertyName, for example:

class myclass{ private $propertyName; public function __construct() { $this->propertyName = “value”; }}

12.What is the difference between include and include_once? What about require?

All three are used to insert other files into the script. Depending on whether url_allow_fopen is approved, this file can be obtained from inside or outside the system. But there are also subtle differences between them:

include(): This function allows you to insert the same file multiple times in the script. If the file does not exist, it will issue a system warning and continue executing the script.

include_once(): It has a similar function to include(). As its name suggests, the relevant file will only be inserted once during the execution of the script.

require(): Similar to include(), it is also used to insert other files into the script, but if the file does not exist, it will issue a system warning. This warning will cause a fatal error and cause the script to terminate execution

13.Which of the following functions can redirect the browser to another page?

redir()

This is not a PHP function and will cause an execution error.

header()

This is the correct answer. header() is used to insert header information and can be used to redirect the browser to another page, for example:

header(“Location: http://www.gosoa.com.cn/”);

location()

This is not a PHP function and will cause an execution error.

redirect()

This is not a PHP function and will cause an execution error.

14. Which of the following functions can be used to open files for reading/writing?

fget()

This is not a PHP function and will cause an execution error.

file_open()

This is not a PHP function and will cause an execution error.

fopen()

This is the correct answer. fopen() can be used to open files for reading/writing. In fact, this function has many options. Please refer to php.net for details.

open_file()

This is not a PHP function and will cause an execution error.

15. What is the difference between mysql_fetch_row() and mysql_fetch_array()?

mysql_fetch_row() stores a database column in a zero-based array, with the first column at array index 0, the second column at index 1, and so on. mysql_fetch_assoc() stores a column of the database in an associative array. The index of the array is the field name. For example, my database query returns the three fields "first_name", "last_name", and "email". The index of the array is "first_name", "last_name" and "email". mysql_fetch_array() can return the values ​​of both mysql_fetch_row() and mysql_fetch_assoc().

16.What is the following code used for? Please explain.

$date='08/26/2003′;print ereg_replace(“([0-9]+)/([0-9]+)/([0-9]+)”,”\2/ \1/\3″,$date);

This is to convert a date from MM/DD/YYYY format to DD/MM/YYYY format. A good friend of mine told me that this regular expression can be disassembled into the following statements. For such a simple expression, there is no need to disassemble it. It is purely for the convenience of explanation:

// Corresponds to one or more 0-9, followed by a slash $regExpression = "([0-9]+)/";// Corresponds to one or more 0-9, followed by another A slash $regExpression .= “([0-9]+)/”;// again corresponds to one or more 0-9$regExpression .= “([0-9]+)”; as for \2/\ 1/\3 is used to correspond to brackets. The first bracket corresponds to the month, the second bracket corresponds to the date, and the third bracket corresponds to the year.

17. Given a line of text $string, how would you write a regular expression to remove the HTML tags in $string?

First of all, PHP has a built-in function strip_tags() to remove HTML tags. Why do you need to write your own regular expression? Okay, let’s treat this as an interview question. I will answer this:

$stringOfText = “

This is a test

”;$expression_r = “/<(.*?)>(.*?) /”;echo preg_replace($expression_r, “\2″, $stringOfText);// Some people say that you can also use /(<[^>]*>)/ $expression_r = “/(<[^> ;]*>)/”;echo preg_replace($expression_r, “”, $stringOfText);

18.What are the differences in how PHP and Perl distinguish arrays and hash tables?

This is why I always tell people to choose the appropriate programming language. How can you answer this question if you only use one language? This question is simple. All array variables in Perl begin with @, such as @myArray, while PHP uses $ as the beginning of all variables, such as $myArray.

As for Perl, % is used to represent a hash table, such as %myHash. There is no difference in PHP, and $ is still used, such as $myHash.

19. How do you use PHP to solve the stateless nature of HTTP?

The two main options are session and cookie. The way to use session is to add session_start() at the beginning of each page, and then use the $_SESSION hash table to store the session variable. As for cookies, you just need to remember one rule: call the set_cookie() function before outputting any text. In addition, just use the $_COOKIE hash table to access all cookie variables.

There is also a less reliable method, which is to use the visitor’s IP address. This method has certain dangers.

20.What is the GD library used for?

This is probably my favorite library. GD has been built into the PHP system since version 4.3.0. This library allows you to process and display graphics files in various formats. Another common use of this library is to create graphics files. An alternative to GD is ImageMagick, but this library is not built into PHP and must be installed on the server by the system administrator.

21. Try to write several methods to output a piece of HTML code.

Well, you can use any output statement in PHP, including echo, print, and printf. Most people use echo as follows:

echo “My string $variable”; You can also use this method:

echo << HTML tags in here as well. The END; remarks must be on a line of its own, and can't contain any extra white space.END;

22. Is PHP better than Perl? Please discuss.

Let's not start a war of words over a simple question. As I often say: "Choose the language that suits the job, and don't adapt the job to the language." I personally think that Perl is very suitable for use as a command line tool, although it It also performs well in web applications, but its true strength can only be fully demonstrated on the command line. Similarly, although PHP can be used in a console environment, I personally think that it performs better in web applications. PHP has a large number of functions specifically designed for web applications, while Perl seems to be designed with the command line in mind. .

Personally, I like both languages. I often used Perl, PHP and Java during college. Unfortunately, I use C# at work, but at home I spend a lot of time practicing PHP, Perl, and Ruby (currently studying ) and Java to keep my skills knowledge up to date. A lot of people ask me about C and C++ and whether they still have a chance to play a role in my applications. My answer is basically "no". My recent work is mainly focused on web development, although C and C++ can also be used. Used to write web pages, but they are not designed for this kind of work after all. "Choose the right language for the job", if I need to write a console application to show the performance comparison of bubble sort, quick sort and merge sort , I will definitely use C/C++. If I needed to write a photo album system, I would use PHP or C# (I think .NET is better for making user interfaces than web pages).

6. Install PHP as an Apache module. In the file http.conf, first use the statement ____ to dynamically load the PHP module,

Then use the statement ____ to cause Apache to process all files with the extension php as PHP scripts.

Answer: LoadModule php5_module “c:/php/php5apache2.dll”;AddType application/x-httpd-php .php

See Reference Manual》Contents》II. Installation and Configuration》6. Installation under Windows System》Apache 2.0.x under Microsoft Windows

7. Both the statements include and require can 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() results in a fatal error; require_once()/include_once()

8. The parameter of a function cannot be a reference to a variable, unless ____ is set to on in php.ini.

Answer: allow_call_time_pass_reference boolean: Whether to enable forcing parameters to be passed by reference when calling functions, see Appendix G of the Reference Manual

9. The meaning of LEFT JOIN in SQL is __, if tbl_user records the student’s name (name) and student number (ID),

tbl_score records the student number (ID), test score (score), and test subject (subject) of the students (some students were expelled after the exam, and there is no record of them). If you want to print out the name of each student and the corresponding For the total score of each subject, you can use the SQL statement____.

Answer: Natural left outer join

create database phpinterview;

use phpinterview

create table tbl_user

(

ID                                                                                                                                                                                                                                                                 

name varchar (50) not null,

primary key (ID)

);

create table tbl_score

(

ID                                                                                                                                                                                                                                                                 

score                                                                                                                                                                                                                             

subject varchar (20) not null

);

insert into tbl_user (ID, name) values ​​(1, ’beimu’);

insert into tbl_user (ID, name) values ​​(2, ‘aihui’);

insert into tbl_score (ID, score, subject) values ​​(1, 90, ‘中文’);

insert into tbl_score (ID, score, subject) values ​​(1, 80, ‘math’);

insert into tbl_score (ID, score, subject) values ​​(2, 86, ‘math’);

insert into tbl_score (ID, score, subject) values ​​(2, 96, ‘中文’);

select A.id,sum(B.score) as sumscore

from tbl_user A left join tbl_score B

on A.ID=B.ID

group by A.id

10. In PHP, heredoc is a special string, and its end mark must be____

Answer: The line containing the end identifier cannot contain any other characters except ";"

11. Write a function that can traverse all files and subfolders in a folder.

function my_scandir($dir)

{

$files=array();

if(is_dir($dir))

{

if($handle=opendir($dir))

{

while(($file=readdir($handle))!==false)

           {

                if($file!="." && $file!="..")

              {

                                                                                                                                                                                                                                                                             

                                                                                   

$files[$file]=my_scandir($dir."/".$file);

          }

              else

                                                                                   

                                                                                                    $files[]=$dir."/".$file;

          }

        }

      }

closedir($handle);

return $files;

} }

}

}

print_r(my_scandir("D:Program FilesInternet ExplorerMUI"));

1. In PHP, the name of the current script (excluding path and query string) is recorded in the predefined variable (1); and the previous page URL linked to the current page is recorded in the predefined variable (2 ) in

//This page address, SCRIPT_NAME can also be: php/test.php

echo $_SERVER['PHP_SELF'].”
”;

//The URL address of the previous page linked to the current page:

echo $_SERVER['HTTP_REFERER'].”
”;

//For other information, see the reference manual: Language Reference》Variables》Predefined variables

// Absolute path name of the previously executed script: D:Inetpubwwwrootphp est.php

echo $_SERVER["SCRIPT_FILENAME"].”
”;

//IP address of the user browsing the current page: 127.0.0.1

echo $_SERVER["REMOTE_ADDR"].”
”;

//Query string (content after the first question mark ? in the URL): id=1&bi=2

echo $_SERVER["QUERY_STRING"].”
”;

//The document root directory where the currently running script is located: d:inetpubwwwroot

echo $_SERVER["DOCUMENT_ROOT"].”
”;

?>

2. Execute the program segment will output __.

//Reference Manual》Language Reference》Operator》Arithmetic Operator》% is the modulo operation, output 0

echo 8%(-2).”
”;

//The result of modulo $a % $b when $a is negative is also negative. Output -2

echo ((-8)%3).”
”;

//Output 2

echo (8%(-3)).”
”;

?>

3. In HTTP 1.0, the meaning of status code 401 is ____; if a "File not found" prompt 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]

4. 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 Al

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