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PHP: Fundamentals

Set A

Please answer the following 50 multiple-choice questions to test your knowledge in PHP fundamentals. You must place your answer file in the submission folder. Within the submission/Q4/set_a folder, create a folder called your github_id.

Which of the following is the correct opening tag for PHP code?
- a) <?php
- b) <php>
- c) <script>
- d) <?=
What does PHP stand for?
- a) Personal Home Page
- b) Pretext Hypertext Processor
- c) PHP: Hypertext Preprocessor
- d) Preprocessor Hyperlink Pages
Which PHP function is used to output text to the browser?
- a) echo
- b) print
- c) display
- d) output
How do you assign a value to a variable in PHP?
- a) Using the assignment operator (=)
- b) Using the set keyword
- c) Using the value keyword
- d) Using the assign function
What is the correct way to end a PHP statement?
- a) With a semicolon (;)
- b) With a colon (:)
- c) With a comma (,)
- d) With a period (.)
Which operator is used for concatenation in PHP?
- a) .
- b) +
- c) -
- d) *
What is the correct way to comment a single line in PHP?
- a) //
- b) #
- c) /* ... */
- d) 
Which function is used to determine the length of a string in PHP?
- a) strlen()
- b) strlength()
- c) stringlength()
- d) length()
What is the output of the following code?
```
$x = 10;
$y = 5;
$result = $x + $y;
echo $result;
```
- a) 15
- b) 10 + 5
- c) $result
- d) Error
What is the correct way to declare an array in PHP?
- a) $fruits = array("Apple", "Banana", "Orange");
- b) $fruits = ["Apple", "Banana", "Orange"];
- c) $fruits = "Apple", "Banana", "Orange";
- d) $fruits = ("Apple", "Banana", "Orange");
How do you access the value at a specific index in an array?
- a) By using square brackets [] and the index number
- b) By using parentheses () and the index number
- c) By using curly braces {} and the index number
- d) By using a period . and the index number

What is the output of the following code?

$num = 7;
if ($num % 2 == 0) {
    echo "Even";
} else {
    echo "Odd";
}

a) Even
b) Odd
c) 7
d) Error

Which function is used to include an external PHP file?
- a) include()
- b) import()
- c) require()
- d) load()
What is the correct way to define a constant in PHP?
- a) define("PI", 3.14);
- b) constant("PI", 3.14);
- c) $PI = 3.14;
- d) const PI = 3.14;
How do you start a session in PHP?
- a) session_start()
- b) start_session()
- c) new Session()
- d) begin_session()
What is the correct way to retrieve a value from a query string in PHP?
- a) $_GET["param"]
- b) $_POST["param"]
- c) $_REQUEST["param"]
- d) $_SERVER["param"]
Which PHP superglobal variable stores cookies?
- a) $_SESSION
- b) $_GET
- c) $_POST
- d) $_COOKIE
What is the correct way to redirect a user to a different page in PHP?
- a) header("Location: newpage.php");
- b) redirect("newpage.php");
- c) load_page("newpage.php");
- d) goto("newpage.php");
What is the output of the following code?
```
$num1 = 5;
$num2 = "10";
$result = $num1 + $num2;
echo $result;
```
- a) 15
- b) 510
- c) Error
- d) 510 (as a string)
What is the correct way to connect to a MySQL database in PHP?
- a) mysqli_connect()
- b) mysql_connect()
- c) pdo_connect()
- d) db_connect()
What is the purpose of prepared statements in PHP?
- a) To prevent SQL injection attacks
- b) To optimize database queries
- c) To execute complex SQL queries
- d) To store frequently used SQL queries
What is the correct way to retrieve the number of rows returned from a MySQL query in PHP?
- a) mysqli_num_rows()
- b) mysql_num_rows()
- c) pdo_num_rows()
- d) db_num_rows()
How do you close a MySQL database connection in PHP?
- a) mysqli_close()
- b) mysql_close()
- c) pdo_close()
- d) db_close()

What is the output of the following code?

$fruit = "Apple";
switch ($fruit) {
    case "Apple":
        echo "It's a fruit.";
        break;
    case "Banana":
        echo "It's a fruit.";
        break;
    default:
        echo "Unknown fruit.";
}

a) It's a fruit.
b) Unknown fruit.
c) Apple
d) Banana

What is the correct way to handle errors in PHP?
- a) Using try...catch blocks
- b) Using if...else statements
- c) Using error_reporting()
- d) Using print_error()
What is the purpose of the __construct() function in PHP classes?
- a) To create a new object instance of the class
- b) To destroy an object instance of the class
- c) To initialize the object's properties and perform setup tasks
- d) To define the behavior of the class methods
What is the correct way to create an object of a class in PHP?
- a) $object = new ClassName();
- b) $object = createObject(ClassName);
- c) $object = instantiate(ClassName);
- d) $object = object(ClassName);

What is the output of the following code?

class Person {
    public $name;
    public function sayHello() {
        echo "Hello, " . $this->name;
    }
}

$person = new Person();
$person->name = "John";
$person->sayHello();

a) Hello, John
b) Hello, Person
c) Error
d) John

How do you access a static property or method of a class in PHP?
- a) By using the :: operator
- b) By using the . operator
- c) By using the -> operator
- d) By using the => operator
What is the purpose of the public access modifier in PHP class properties and methods?
- a) It allows access to the property or method from anywhere
- b) It allows access to the property or method only within the class
- c) It allows access to the property or method within the class and its subclasses
- d) It restricts access to the property or method

What is the output of the following code?

function add(&$num) {
    $num += 10;
}

$number = 5;
add($number);
echo $number;

a) 5
b) 10
c) 15
d) Error

What is the correct way to read a file line by line in PHP?
- a) Using the fread() function
- b) Using the file_get_contents() function
- c) Using the fgets() function
- d) Using the file() function
What is the purpose of the file_exists() function in PHP?
- a) To check if a file or directory exists
- b) To read the contents of a file
- c) To write data to a file
- d) To delete a file or directory

What is the output of the following code?

function multiply($num1, $num2 = 2) {
    return $num1 * $num2;
}

$result1 = multiply(5);
$result2 = multiply(5, 3);

echo $result1 . ", " . $result2;

a) 5, 15
b) 10, 15
c) 5, 6
d) Error

What is the correct way to remove leading and trailing whitespace from a string in PHP?
- a) trim()
- b) strip()
- c) removeWhitespace()
- d) cleanWhitespace()
What is the output of the following code?
```
$x = 10;
echo ++$x;
```
- a) 10
- b) 11
- c) Error
- d) ++10
What is the purpose of the foreach loop in PHP?
- a) To iterate over elements in an array or collection
- b) To execute a block of code repeatedly
- c) To conditionally execute code based on a condition
- d) To perform a specific task a fixed number of times
What is the correct way to check if a variable is empty in PHP?
- a) empty()
- b) isNull()
- c) isBlank()
- d) isEmpty()
What is the output of the following code?
```
$str = "Hello World";
echo str_replace("World", "PHP", $str);
```
- a) Hello World
- b) Hello PHP
- c) World PHP
- d) Error
What is the purpose of the array_push() function in PHP?
- a) To add elements to the beginning of an array
- b) To remove elements from an array
- c) To merge two or more arrays
- d) To add elements to the end of an array

What is the output of the following code?

$numbers = [1, 2, 3, 4, 5];
$sum = array_sum($numbers);
echo $sum;

a) 1
b) 15
c) 5
d) Error

What is the purpose of the explode() function in PHP?
- a) To split a string into an array
- b) To combine multiple strings into one string
- c) To reverse the characters in a string
- d) To convert a string to lowercase
What is the output of the following code?
```
$number = 3;
echo pow($number, 2);
```
- a) 3
- b) 9
- c) 6
- d) Error
What is the purpose of the date() function in PHP?
- a) To retrieve the current date and time
- b) To format a date and time string
- c) To compare two dates
- d) To add or subtract days from a date
What is the output of the following code?
```
$age = 25;
echo ($age >= 18) ? "Adult" : "Minor";
```
- a) Adult
- b) Minor
- c) 25
- d) Error
What is the purpose of the header() function in PHP?
- a) To set HTTP headers for the response
- b) To include an external PHP file
- c) To redirect the user to a different page
- d) To retrieve the value of a request header
What is the output of the following code?
```
$str = "Hello";
echo strlen($str);
```
- a) 5
- b) 6
- c) 4
- d) Error
What is the purpose of the json_encode() function in PHP?
- a) To convert a PHP array or object into a JSON string
- b) To convert a JSON string into a PHP array or object
- c) To encode a URL string
- d) To encrypt data

What is the output of the following code?

$colors = ["Red", "Green", "Blue"];
$color = "Red";

if (in_array($color, $colors)) {
    echo "Color found!";
} else {
    echo "Color not found!";
}

a) Color found!
b) Color not found!
c) Red
d) Error

What is the purpose of the filter_input() function in PHP?
- a) To filter and sanitize user input data
- b) To retrieve the value of a request header
- c) To validate email addresses
- d) To decode a JSON string

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