Saturday, 1 June 2019
Monday, 24 December 2018
Interview Questions for Fresher Set-10
91) In PHP, objects are they passed by value or by reference?
In PHP, objects passed by value.
92) What does accessing a class via :: means?
:: is used to access static methods that do not require object initialization.
93) How is the ternary conditional operator used in PHP?
It is composed of three expressions: a condition, and two operands describing what instruction should be performed when the specified condition is true or false as follows:
Expression_1?Expression_2 : Expression_3;
94) What is the function func_num_args() used for?
The function func_num_args() is used to give the number of parameters passed into a function.
95) If the variable $var1 is set to 10 and the $var2 is set to the character var1, what's the value of $$var2?
$$var2 contains the value 10.
96) How is it possible to cast types in PHP?
The name of the output type has to be specified in parentheses before the variable which is to be cast as follows:
* (int), (integer) - cast to integer
* (bool), (boolean) - cast to boolean
* (float), (double), (real) - cast to float
* (string) - cast to string
* (array) - cast to array
* (object) - cast to object
97) When is a conditional statement ended with endif?
When the original if was followed by: and then the code block without braces.
In PHP, objects passed by value.
92) What does accessing a class via :: means?
:: is used to access static methods that do not require object initialization.
93) How is the ternary conditional operator used in PHP?
It is composed of three expressions: a condition, and two operands describing what instruction should be performed when the specified condition is true or false as follows:
Expression_1?Expression_2 : Expression_3;
94) What is the function func_num_args() used for?
The function func_num_args() is used to give the number of parameters passed into a function.
95) If the variable $var1 is set to 10 and the $var2 is set to the character var1, what's the value of $$var2?
$$var2 contains the value 10.
96) How is it possible to cast types in PHP?
The name of the output type has to be specified in parentheses before the variable which is to be cast as follows:
* (int), (integer) - cast to integer
* (bool), (boolean) - cast to boolean
* (float), (double), (real) - cast to float
* (string) - cast to string
* (array) - cast to array
* (object) - cast to object
97) When is a conditional statement ended with endif?
When the original if was followed by: and then the code block without braces.
98) How is a constant defined in a PHP script?
The define() directive lets us defining a constant as follows:
define ("ACONSTANT", 123);
99) How can you pass a variable by reference?
To be able to pass a variable by reference, we use an ampersand in front of it, as follows $var1 = &$var2
100) Will a comparison of an integer 12 and a string "13" work in PHP?
"13" and 12 can be compared in PHP since it casts everything to the integer type.
Interview Questions for Fresher Set-9
81) What is the difference between session_unregister() and session_unset()?
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
82) When do sessions end?
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
82) When do sessions end?
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
83) What is the meaning of a Persistent Cookie?
A persistent cookie is permanently stored in a cookie file on the browser's computer. By default, cookies are temporary and are erased if we close the browser.
84) How can you propagate a session id?
You can propagate a session id via cookies or URL parameters.
85) How to initiate a session in PHP?
The use of the function session_start() lets us activating a session.
86) what is the definition of a session?
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
87) What is faster?
1- Combining two variables as follows:
$variable1 = 'Hello ';
$variable2 = 'World';
$variable3 = $variable1.$variable2;
Or
2- $variable3 = "$variable1$variable2";
$variable3 will contain "Hello World". The first code is faster than the second code especially for large large sets of data.
88) What's the difference between __sleep and __wakeup?
__sleep returns the array of all the variables that need to be saved, while __wakeup retrieves them.
89) Are Parent constructors called implicitly inside a class constructor?
No, a parent constructor have to be called explicitly as follows:
parent::constructor($value)
90) In PHP, objects are they passed by value or by reference?
In PHP, objects passed by value.
Interview Questions for Fresher Set-8
71) what the difference between the 'BITWISE AND' operator and the 'LOGICAL AND' operator?
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
72) What does the scope of variables mean?
The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
72) What does the scope of variables mean?
The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
73) What does $_COOKIE mean?
$_COOKIE is an associative array of variables sent to the current PHP script using the HTTP Cookies.
74) What does $_ENV mean?
$_ENV is an associative array of variables sent to the current PHP script via the environment method.
75) How can we change the maximum size of the files to be uploaded?
We can change the maximum size of files to be uploaded by changing upload_max_filesize in php.ini.
76) How can we get the error when there is a problem to upload a file?
$_FILES['userfile']['error'] contains the error code associated with the uploaded file.
77) What is the difference between $_FILES['userfile']['name'] and $_FILES['userfile']['tmp_name']?
$_FILES['userfile']['name'] represents the original name of the file on the client machine,
$_FILES['userfile']['tmp_name'] represents the temporary filename of the file stored on the server.
78) What does $_FILES means?
$_FILES is an associative array composed of items sent to the current script via the HTTP POST method.
79) What does $_SERVER mean?
$_SERVER is an array including information created by the web server such as paths, headers, and script locations.
80) What does $GLOBALS mean?
$GLOBALS is associative array including references to all variables which are currently defined in the global scope of the script.
Interview Questions for Fresher Set-7
61) what is the difference between for and foreach?
for is expressed as follows:
for (expr1; expr2; expr3)
statement
The first expression is executed once at the beginning. In each iteration, expr2 is evaluated. If it is TRUE, the loop continues, and the statements inside for are executed. If it evaluates to FALSE, the execution of the loop ends. expr3 is tested at the end of each iteration.
However, foreach provides an easy way to iterate over arrays, and it is only used with arrays and objects.
62) What is the difference between the functions strstr() and stristr()?
The string function strstr(string allString, string occ) returns part of allString from the first occurrence of occ to the end of allString. This function is case-sensitive. stristr() is identical to strstr() except that it is case insensitive.
63) How can we determine whether a variable is set?
The boolean function isset determines if a variable is set and is not NULL.
for is expressed as follows:
for (expr1; expr2; expr3)
statement
The first expression is executed once at the beginning. In each iteration, expr2 is evaluated. If it is TRUE, the loop continues, and the statements inside for are executed. If it evaluates to FALSE, the execution of the loop ends. expr3 is tested at the end of each iteration.
However, foreach provides an easy way to iterate over arrays, and it is only used with arrays and objects.
62) What is the difference between the functions strstr() and stristr()?
The string function strstr(string allString, string occ) returns part of allString from the first occurrence of occ to the end of allString. This function is case-sensitive. stristr() is identical to strstr() except that it is case insensitive.
63) How can we determine whether a variable is set?
The boolean function isset determines if a variable is set and is not NULL.
64) How is it possible to parse a configuration file?
The function parse_ini_file() enables us to load in the ini file specified in filename and returns the settings in it in an associative array.
65) What does the expression Exception::__toString means?
Exception::__toString gives the String representation of the exception.
66) what is the difference between Exception::getMessage and Exception:: getLine?
Exception::getMessage lets us getting the Exception message and Exception::getLine lets us getting the line in which the exception occurred.
67) What is the goto statement useful for?
The goto statement can be placed to enable jumping inside the PHP program. The target is pointed by a label followed by a colon, and the instruction is specified as a goto statement followed by the desired target label.
68) How can we determine whether a PHP variable is an instantiated object of a certain class?
To be able to verify whether a PHP variable is an instantiated object of a certain class we use instanceof.
69) What is the differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).
81) What does the array operator '===' means?
$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
70) What are the two main string operators?
The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.
Interview Questions for Fresher Set-6
51) Is it possible to use COM component in PHP?
Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.
52) What is the default session time in PHP?
The default session time in php is until the closing of the browser
53) Is it possible to destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration time.
54) Is it possible to extend the execution time of a PHP script?
The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.
55) How can we pass the variable through the navigation between the pages?
It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.
56) What is the difference between characters \034 and \x34?
\034 is octal 34 and \x34 is hex 34.
57) What are the three classes of errors that can occur in PHP?
The three basic classes of errors are notices (non-critical), warnings (serious errors) and fatal errors (critical errors).
58) Is it possible to protect special characters in a query string?
Yes, we use the urlencode() function to be able to protect special characters.
59) What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
60) Is it possible to submit a form with a dedicated button?
It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">
Interview Questions for Fresher Set-5
41) Which cryptographic extension provide generation and verification of digital signatures?
The PHP-OpenSSL extension provides several cryptographic operations including generation and verification of digital signatures.
42) What is the most convenient hashing method to be used to hash passwords?
It is preferable to use crypt() which natively supports several hashing algorithms or the function hash() which supports more variants than crypt() rather than using the common hashing algorithms such as md5, sha1 or sha256 because they are conceived to be fast. Hence, hashing passwords with these algorithms can create vulnerability.
43) How is it possible to return a value from a function?
A function returns a value using the instruction 'return $value;'.
44) How can we define a variable accessible in functions of a PHP script?
This feature is possible using the global keyword.
45) what is the static variable in function useful for?
A static variable is defined within a function only the first time, and its value can be modified during function calls as follows:
<!--?php function testFunction() { static $testVariable = 1; echo $testVariable; $testVariable++; } testFunction(); //1 testFunction(); //2 testFunction(); //3 ?-->
46) Is it possible to remove the HTML tags from data?
The strip_tags() function enables us to clean a string from the HTML tags.
47) What does the function get_magic_quotes_gpc() means?
The function get_magic_quotes_gpc() tells us whether the magic quotes is switched on or no.
48) How can we automatically escape incoming data?
We have to enable the Magic quotes entry in the configuration file of PHP.
49) How is it possible to remove escape characters from a string?
The stripslashes function enables us to remove the escape characters before apostrophes in a string.
50) How do I escape data before storing it in the database?
The addslashes function enables us to escape data before storage into the database.
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