PHP

Question 1

PHP can be run without a server.

Answer 1

False.

Question 2

Who originally authored PHP, and when?

Answer 2

Rasmus Lerdorf, in 1994.

Question 3

PHP is an open source product.

Answer 3

True.

Question 4

PHP is a client-side scripting language whose scripts are embedded in HTML documents.

Answer 4

False, PHP is a server-side scripting language.

Question 5

Is PHP statically or dynamically typed?

Answer 5

Dynamic.

Question 6

PHP is purely interpreted, meaning what?

Answer 6

PHP is executed directly by the interpreter without being compiled into machine code first.

Question 7

In what version of PHP was OOP functionality first added?

Answer 7

PHP 3.

Question 8

In what version of PHP was object handling completely rewritten?

Answer 8

PHP 5.

Question 9

How is internal PHP code embedded in HTML documents?

Answer 9

By inserting the code between the “<?php” and “?>” tags.

Question 10

How is external PHP code embedded in HTML documents?

Answer 10

<?php include(“script.php”); ?>

Question 11

What are the three ways of writing comments in PHP?

Answer 11

…

//…, #…, or /* … */

Question 12

PHP variable names must always be preceded by a ‘$’.

Answer 12

True.

Question 13

The following unassigned (unbound) variable has what value?
$x;

Answer 13

Null.

Question 14

The following are both valid print methods:
print “Hello World! < br >”;
echo “Hello World! < br >”;

Answer 14

True.

Question 15

The following are both valid print methods:
print (“Hello World! < br >”);
echo (“Hello World! < br >”);

Answer 15

True.

Question 16

The following will print the value stored in $x:
echo “The value is: $x”;

Answer 16

True.

Question 17

The following will print the value stored in $x:
echo “The value is: “ + $x;

Answer 17

False - this will print ‘0’, as the compiler attempts a numerical addition.

Question 18

The following will print the value stored in $x:
echo “The value is: “.$x;

Answer 18

True.

Question 19

The following will print the value stored in $x:
echo “The value is: “, $x;

Answer 19

True.

Question 20

How many primitive types are there in PHP?

Answer 20

8.

Question 21

What are the 3 categories of primitive types in PHP?

Answer 21

Scalar types, compound types, and special types.

Question 22

What are the 4 (primitive) scalar types in PHP?

Answer 22

Boolean, Integer, Double, String.

Question 23

What are the 2 (primitive) compound types in PHP?

Answer 23

Array and Object.

Question 24

What are the 2 (primitive) special types in PHP?

Answer 24

Resource and NULL.

Question 25

7E2 and 7e2 are both valid numeric literals in PHP.

Answer 25

True.

Question 26

7,000 and 7,000,000 are both valid numeric literals in PHP.

Answer 26

False, neither are.

Question 27

7.2E-2 is a valid numeric literal in PHP.

Answer 27

True.

Question 28

0x0A and 0X0A are both valid numeric literals in PHP.

Answer 28

True.

Question 29

By default, how many bytes per character in PHP?

Answer 29

1

Question 30

The native PHP string is “Unicoded” (outputted as a Unicode string).

Answer 30

False.

Question 31

You cannot output a Unicode string in PHP.

Answer 31

False - you can.

Question 32

What character is used to delimit String literals in PHP?

Answer 32

Either single or double quotes.

Question 33

What is the difference between single and double quote delimiters for string literals in PHP?

Answer 33

They do not allow the same substitutions.

Question 34

What will be printed to the html document?
echo ‘he\’s cool \n’;

Answer 34

he’s cool \n

Question 35

What will be printed to the html document?
$x = ‘me’;
echo ‘he\’s “cool\” like $x’;

Answer 35

he’s “cool\” like $x

Question 36

What will be printed to the html document?
echo “he\’s cool \n”;

Answer 36

he\’s cool

Question 37

What will be printed to the html document?
$x = ‘me’;
echo “he\’s \“cool\” like $x”;

Answer 37

he\’s “cool” like me

Question 38

What will be displayed on the browser?
$sum = 100;
print(‘The sum is $sum <br> Is that ok?’);

Answer 38

The sum is $sum
Is that ok?

Question 39

The following will result in how many empty lines between characters ‘a’ and ‘b’?
print(“a\n”);
print(“<br>”);
print(“b\n”);

Answer 39

0

Question 40

What is the output of the following code on the browser?
$a = “Guns N\’ Roses”;
print(“\$a”);

Answer 40

$a

Question 41

Boolean values in PHP are case senstive.

Answer 41

False.

Question 42

In PHP, 0 and 0.0 evaluate to Boolean false.

Answer 42

True.

Question 43

In PHP, both “” and NULL evaluate to Boolean false.

Answer 43

True.

Question 44

In PHP, “0” evaluates to Boolean false.

Answer 44

True.

Question 45

In PHP, ‘0’ evaluates to Boolean false.

Answer 45

True.

Question 46

The following code sets $x’s value to what?
unset($x);

Answer 46

NULL.

Question 47

When does the following expression return true?
isset($x);

Answer 47

When $x’s value isn’t NULL.

Question 48

NULL is coerced to 0 if the context specifies a number.

Answer 48

True.

Question 49

NULL is coerced to “null” if the context specifies a string.

Answer 49

False - it is coerced to an empty string.

Question 50

What is phpinfo()?

Answer 50

phpinfo() is a predefined function that outputs information about the PHP configuration and environment.

Question 51

What does round(5.5) return?

Answer 51

6

Question 52

What does PHP’s built in srand() function do?

Answer 52

srand() seeds a random number generator. There is no reason to do this past PHP 4.2.0.

Question 53

What does rand() return if we don’t pass any arguments?

Answer 53

Nothing, rand() requires 2 arguments.

Question 54

Which PHP function rounds doubles up, and which rounds down?

Answer 54

ceil() and floor().

Question 55

Which php function returns the absolute value of a number?

Answer 55

abs()

Question 56

Which PHP functions return the smallest/greatest values out of a list of values?

Answer 56

min() and max()

Question 57

What operator is used in PHP for string concatenation?

Answer 57

.

Question 58

Can commas be used for string concatenation?

Answer 58

No, but echo can take multiple arguments separated by commas.

Question 59

The second line exhibits a valid method of concatenation.
$a = “Hello “;
$a .= “World!”

Answer 59

True.

Question 60

What does strlen($str) return?

Answer 60

The length of $str.

Question 61

What does strcmp($str1, $str2) return?

Answer 61

0 if the strings are identical, a negative number if the first string “comes” before the second (in the ASCII sequence) and a positive number if the second string comes before the first.

Question 62

What does strpos($str1, $str2) return?

Answer 62

The character position of $str2’s position in $str1, if it exists.

Question 63

What does substr($str, $int) return?

Answer 63

The substring of $str, from index $int to the end.

Question 64

What does chop($str) return?

Answer 64

$str but will all whitespace removed from its end.

Question 65

What does trim($str) return?

Answer 65

$str but will all whitespace removed from both ends.

Question 66

What does ltrim($str) return?

Answer 66

$str but will all whitespace removed from its beginning.

Question 67

What does strtolower($str) return?

Answer 67

$str in all lowercase.

Question 68

What does strtoupper($str) return?

Answer 68

$str in all uppercase.

Question 69

what does the following code output?
echo substr(“Apples are good”, 7, 2);

Answer 69

ar

Question 70

what does the following code output?
echo strcmp(‘a’, ‘c’);

Answer 70

-2

Question 71

What does strpos($str1, $str2) return if $str2 isn’t found in $str1? (PHP)

Answer 71

False.

Question 72

What does the following code output?
$str = ‘Look at the sea’;
$str[strlen($str)-1] = ‘e’;
echo $str;

Answer 72

Look at the see

Question 73

What is the output of the following code?
$x = “hi”[1];
echo $x;

Answer 73

i

Question 74

In PHP, how many ways are there to explicitly convert (cast) a value?

Answer 74

3

Question 75

Write 3 ways to cast the value in $x to an integer in PHP.

Answer 75

(int) $x
intval($x)
settype($x, “integer”)

Question 76

How many ways are there to determine the type of a variable in PHP? What are they?

Answer 76

2 - gettype($x) or is_integer($x).

Question 77

gettype($x) returns what if $x’s type can’t be determined?

Answer 77

“unknown”

Question 78

When can a string be converted (or coerced) to an integer? (PHP)

Answer 78

If it begins with an integer.

Question 79

In PHP, when can a string be converted (or coerced) to a double? (4 cases)

Answer 79

If the string begins with a double, a period, an e or an E.

Question 80

If a PHP string does not begin with a sign or a digit, then what number is it implicitly converted (coerced) to?

Answer 80

0

Question 81

What is NULL coerced to if the context specifies a number?

Answer 81

0

Question 82

What is NULL coerced to if the context specifies a string?

Answer 82

”” (empty string)

Question 83

What is the output of the following?
$str = ‘5.1’;
print($str+1);

Answer 83

6.1

Question 84

What is the output of the following?
$str = ‘5.1’;
print((int)$str);

Answer 84

5

Question 85

What is the output of the following?
$str = ‘5.5’;
print((int)$str);

Answer 85

5 - casting rounds down.

Question 86

Which is faster, echo or print?

Answer 86

echo - but only slightly.

Question 87

When using printf, what does %10s specify?

Answer 87

A character string field of 10 characters.

Question 88

When using printf, what does %6d specify?

Answer 88

An integer field of six digits.

Question 89

When using printf, what does %5.2f specify?

Answer 89

A float or double field of 5 digits before the decimal, and 2 digits after the decimal.

Question 90

What’s the difference between != / == and !== / === ?

Answer 90

!= & == are type coercing.

Question 91

Are >= & <= type coercing?

Answer 91

Yes.

Question 92

Which is coerced when a string and a number are compared?

Answer 92

The string is coerced to a number, and numeric comparison is used.

Question 93

If two strings are compared, PHP will never coerce both into numbers.

Answer 93

False - both will be coerced into numbers if both “look like” numbers.

Question 94

Comparison operators should generally be used to compare strings.

Answer 94

False - strcmp() is (generally) preferred.

Question 95

and, or, and xor are valid PHP Boolean operators.

Answer 95

True.

Question 96

Which has higher precedence between && / || and the ‘and’ / ‘or’ Boolean operators?

Answer 96

&& / || have higher precendence.

Question 97

switch ($val) {
case “0”: echo “zero”; break;
default: echo “not zero”;
}
Is this a valid PHP switch statement structure?

Answer 97

Yes.

Question 98

The following constructs a valid array:
$list = array(1, 3, 5, 7, 9);

Answer 98

True.

Question 99

The following constructs a valid array:
$list = array(1 => “Cessna”,
2 => “C210”,
3 => 1960,
4 => “sold”);

Answer 99

True.

Question 100

The following keys can be replaced with strings:
$list = array(1 => “Cessna”,
2 => “C210”,
3 => 1960,
4 => “sold”);

Answer 100

True.

Question 101

foreach($list as $key) allows you to iterate over the keys in $list.

Answer 101

False, this notation will iterate over the values, where each value can referred to by the $key variable.

Question 102

Write a foreach loop that iterates over the keys AND values of a $list.

Answer 102

foreach($list as $key => $value)

Question 103

The following allows you to iterate over keys:
foreach($list as $key =>)

Answer 103

False - this results in a parse error.

Question 104

Where is the value ‘5’ placed in $list?
$list[] = 5;

Answer 104

At the last available index.

Question 105

$nums = array(1, 2, 3);
Write a single line of code that assigns each value in $nums to its own variable, such as $a, $b, $c.

Answer 105

list($a, $b, $c) = $nums;

Question 106

What method accepts an array, and returns an array of the keys from the passed array?

Answer 106

array_keys()

Question 107

What method accepts an array, and returns an array of the values from the passed array? (PHP)

Answer 107

array_values()

Question 108

What values are used as keys for the arrays constructed by array_keys() and array_values()?

Answer 108

Integer numbers, starting from 0.

Question 109

What method returns true if the passed value exists as a key in the passed array?

Answer 109

array_key_exists()

Question 110

What is the order of parameters passed to array_key_exists()?

Answer 110

array_key_exists($key, $list)

Question 111

How can you delete an array in PHP?

Answer 111

unset($list);

Question 112

The following is valid:
unset($list[4]);

Answer 112

True.

Question 113

How do you check whether $list is an actual array?

Answer 113

is_array($list)

Question 114

How do you check whether the value $x exists in $list?

Answer 114

in_array($x, $list)

Question 115

How do you get the length of an array?

Answer 115

sizeof($list)

Question 116

What is the output of the following code?
$list[4] = 1; $list[1] = 17;
$list[2] = 3; unset($list[2]);
foreach($list as $key => $value)
echo “$key $value <br>”;

Answer 116

4 1
1 17

Question 117

Create an array of every word in $str (words separated by spaces).

Answer 117

explode(“ “, $str)

Question 118

Create a string containing every value in $list (separate each value by a space).

Answer 118

implode(“ “, $list)

Question 119

What is the output of the following code?
$list = array(“A”, “B”, “C”, “D”);
echo current($list);

Answer 119

A

Question 120

What is the output of the following code?
$list = array(“A”, “B”, “C”, “D”);
echo next($list);

Answer 120

B

Question 121

What does each($list) return?

Answer 121

A key-value pair of the “current” element. This method however has been deprecated.

Question 122

Write another way to accomplish the following:
$list[] = $x;

Answer 122

array_push($list, $x);

Question 123

Write another way to accomplish the following:
unset($list[sizeof($list) - 1]);

Answer 123

array_pop($list);

Question 124

sort() sorts the array based off what? Are key/value relationships preserved?

Answer 124

sort() sorts the values and removes existing keys.

Question 125

asort() sorts the array based off what? Are key/value relationships preserved?

Answer 125

asort() sorts the values and keeps key/value relationships - intended for hashes.

Question 126

When is rsort() used?

Answer 126

To sort the values of an array into reverse order.

Question 127

When is ksort used?

Answer 127

To sort the elements of an array by the keys, maintaining the key/value relationships.

Question 128

When is krsort() used?

Answer 128

To sort the elements of an array by the keys into reverse order.

Question 129

PHP functions can be called before being defined.

Answer 129

True - the entire document is parsed prior to execution.

Question 130

Can you overload functions in PHP?

Answer 130

No.

Question 131

Can PHP functions have a variable number of parameters?

Answer 131

Yes.

Question 132

Can PHP function definitions be nested?

Answer 132

Yes.

Question 133

Are PHP function names case sensitive?

Answer 133

No.

Question 134

Can the return keyword be omitted from PHP function definitions?

Answer 134

Yes - its omission implies a void function.

Question 135

Does PHP crash if more parameters are passed to a function than it is defined to accept?

Answer 135

No - the extra parameters are ignored.

Question 136

Does PHP crash if less parameters are passed to a function than it is defined to accept?

Answer 136

No - the unmatched formal parameters are unbound (unless they’ve been given default values).

Question 137

In PHP, by default, are parameters passed by value, or by reference?

Answer 137

By value.

Question 138

How can you specify a pass-by-reference for a specific parameter in PHP?

Answer 138

Precede it with an ampersand:
function f(&$x) { … }

Question 139

In PHP functions, can objects and arrays be returned in the same way as other primitive types?

Answer 139

Yes.

Question 140

How can a function be made to return a reference?

Answer 140

Preceding the name of the function with an ampersand:
function &f() { … }

Question 141

What is the output of the following code?
$a = 1; $b = 2; $c = 0;
function maxx(&$max,$a,$b) {
if($a>$b) $max = $a;
else $max = $b;
$a = 0;
}
maxx($c,$a,$b);
echo $c.” “.$a;

Answer 141

2 1

Question 142

Do function variables live (exist) past the end of the function execution?

Answer 142

Normally, no.

Question 143

What is the scope of an undeclared variable in a function?

Answer 143

It has the scope of the function.

Question 144

How could you access a variable $x defined outside a function, from within that function.

Answer 144

global $x;
(Prior to the manipulation of $x).

Question 145

What is the output of the following code?
$a = 1; $b = 2;
function Sum() {
global $a, $b;
$b = $a + $b;
}
Sum();
echo $b;

Answer 145

3

Question 146

What PHP function checks whether a string matches a specified regex? What is the order of its parameters?

Answer 146

preg_match(regex, str [, array]);

Question 147

What does the optional 3rd parameter do in preg_match()?

Answer 147

Passing an empty array as a third parameter means that array will be filled with all matches of pattern matching operation.

Question 148

What does preg_match() return?

Answer 148

A Boolean (either true or false).

Question 149

What PHP method splits a string into an array using a specified regex as a delimiter?

Answer 149

preg_split(regex,str);

Question 150

In PHP, forms may be handled by the same document that
creates the form.

Answer 150

True.

Question 151

What 2 methods can be used to transmit form data in PHP?

Answer 151

GET or POST.

Question 152

How are names associated with their values in a query string?

Answer 152

By an equals sign: name = value

Question 153

What types of characters are substituted with something else in query strings?

Answer 153

Special characters and spaces.

Question 154

In query strings, what are special characters and spaces replaced by?

Answer 154

By % followed by the hex code for that character.

Question 155

What common name must you give to all checkbox widgets to obtain an array of their values.

Answer 155

Something followed by ‘[]’.

Question 156

Write a PHP class header for a Person object.

Answer 156

class Person { … }

Question 157

How would you define 2 attributes (a1 & a2) within a class definition in PHP?

Answer 157

public $a1;
public $a2;

Question 158

Define a constructor for a PHP class, C1, that has two attributes (a1 & a2).

Answer 158

public function __construct($a1, $a2) {
$this->a1 = $a1;
$this->a2 = $a2;
}

Question 159

Write a public class method that returns a string containing both its attributes, a1 & a2.

Answer 159

public function greeting() {
return “{$this->a1} {$this->a2}”;
}

Question 160

Can class methods be static in PHP?

Answer 160

Yes.

Question 161

What keyword should never be used in a static class method in PHP?

Answer 161

this (followed by ->)

Question 162

How are cookies created in PHP?

Answer 162

setcookie() method.

Question 163

What are the parameters accepted by the setcookie() method?

Answer 163

setcookie(cookie_name, cookie_value, lifetime)

Question 164

Can cookies be created at any time?

Answer 164

No, they must be created before any other HTML
is created by the script.

Question 165

How could you iterate through all cookies?

Answer 165

Using the $_COOKIE array.

Question 166

What does a cookie set look like in the http transaction? (server to client)

Answer 166

Set-Cookie: name=value;expires= …;path=/

Question 167

What does a cookie get look like in the http transaction? (client to server)

Answer 167

Cookie: name=value

Question 168

With your browser, you can view, delete and block cookies.

Answer 168

True.

Question 169

Where are cookies stored (passed)?

Answer 169

In the HTTP request header.

Question 170

Set a cookie to expire in a day from now.

Answer 170

setcookie(“key”, “value”, time() + 86400);

Question 171

How can you check whether a specific cookie has been set?

Answer 171

isset($_COOKIE[“key”])

Question 172

How can you delete a cookie?

Answer 172

setcookie(“key”, “”, time() - 1);

Question 173

Does JS have built in ways of setting/getting cookies?

Answer 173

No.

Question 174

Write a JS function to set cookies.

Answer 174

function setCookie(c_name,value,exdays) {
var exdate = new Date();
exdate.setDate(exdate.getDate() + exdays);
var c_value=escape(value) + ((exdays==null) ? “” : “;
expires=”+exdate.toUTCString());
document.cookie=c_name + “=” + c_value;
}

Question 175

Create an array of all cookies in JS, similar to $_COOKIES in PHP.

Answer 175

ARRcookies=document.cookie.split(“;”);

Question 176

Are cookies returned to all servers?

Answer 176

No, only to the servers that created them.

Question 177

Why may systems that depend on cookies fail?

Answer 177

If the browser refuses to store them.

Question 178

How are sessions similar to cookies?

Answer 178

Holds info about one single user, and passes info between pages.

Question 179

How are sessions different from cookies?

Answer 179

Information is stored server side, and session info is deleted after the user has left the website (if not saved).

Question 180

How does PHP track sessions?

Answer 180

PHP creates and maintains a session tracking id.

Question 181

Where is the session id stored?

Answer 181

Either stored in a cookie or propagated in the URL.

Question 182

What PHP function creates a session id?

Answer 182

session_start()

Question 183

Following session id creation, what do subsequent calls to session_start() do?

Answer 183

Subsequent calls to session_start() retrieve any session
variables that were previously registered in the session.

Question 184

How do you register a session variable?

Answer 184

using $_SESSION[‘var_name’].

Question 185

What restriction is put on the session_start() call if cookie-based sessions are being used?

Answer 185

It must be called before outputting anything to the browser.

Question 186

How do you retrieve a session variable?

Answer 186

using $_SESSION[‘var_name’].

Question 187

How do you delete a specific session variable?

Answer 187

unset($_SESSION[‘name’]);

Question 188

How do you completely destroy a session?

Answer 188

session_destroy();

Question 189

Does session_destroy() unset global variables? What about the session cookie?

Answer 189

No, but all other data associated with the current session is destroyed.

Question 190

How can session variables be used again following session_destory()?

Answer 190

By first calling session_start() again.

Question 191

What method returns a “file pointer”?

Answer 191

fopen();

Question 192

What are the parameters of fopen()?

Answer 192

fopen(“filename.txt”, “x”);
where x is the use indicator.

Question 193

List all the file use indicators.

Answer 193

r, r+, w, w+, a, a+.

Question 194

Describe the ‘r’ use indicator.

Answer 194

Read only. File pointer initialized to the beginning of the file.

Question 195

Describe the ‘r+’ use indicator.

Answer 195

Read and write and existing file. File pointer initialized at the beginning - read and write operations both move the same pointer.

Question 196

Describe the ‘w’ use indicator.

Answer 196

Write only, initializes file pointer to the beginning of the file. Creates the file if it does not exist.

Question 197

Describe the ‘w+’ use indicator.

Answer 197

Write and read, initializes file pointer to the beginning of the file. Creates the file if it does not exist. Always initializes file pointer to beginning before writing - destroying existing data.

Question 198

Describe the ‘a’ use indicator.

Answer 198

Write only, initializes file pointer to the end of the file if it exists. Creates the file if it does not exist, and puts file pointer to the beginning.

Question 199

Describe the ‘a+’ use indicator.

Answer 199

Read and write, creating the file if necessary; new data is written to the end of existing data.

Question 200

How do you check if a file exists?

Answer 200

file_exists($filename)

Question 201

How do you close a file?

Answer 201

f_close($file);

Question 202

what are the parameters of the fread() method?

Answer 202

fread($file_var, $bytestoread)

Question 203

What method returns the size of a file (in bytes)?

Answer 203

filesize($file);

Question 204

What method returns the next car of an open $file?

Answer 204

fgetc($file)

Question 205

Write a while loop that reads characters until the end of the file.

Answer 205

while(!feof($file_var)) {
$ch = fgetc($file_var);
}

Question 206

Use fseek() to jump to the beginning of $file.

Answer 206

fseek($file, 0);

Question 207

Use fseek() to jump to the 1000th byte of $file.

Answer 207

fseek($file, 1000);

Question 208

Use fseek() to jump 100 bytes ahead of the current position in $file.

Answer 208

fseek($file, 100, SEEK_CUR);

Question 209

Use fseek() to jump 100 bytes behind of the current position in $file.

Answer 209

fseek($file, -100, SEEK_CUR);

Question 210

Use fseek() to jump 100 bytes behind the end of $file.

Answer 210

fseek($file, -100, SEEK_END);

Question 211

Use a PHP function to write “Hello World” to $file.

Answer 211

fwrite($file, “Hello World”);

Question 212

Does fwrite() return anything?

Answer 212

Yes, it returns the number of bytes written.