Which PHP function is used to check if a function exists before calling it?

What is the output of the following PHP code?
<?php
function uppercase($str) {
return strtoupper($str);
}
echo uppercase('hello');
?

A). HELLO

B). hello

C). Uppercase

D). Undefined function: uppercase

Which of the following statements about returning values from PHP functions is true?

A). PHP functions can return multiple values simultaneously

B). PHP functions cannot return values

C). PHP functions must always return a value

D). PHP functions can only return values of type string

Which PHP function is used to return a value from a function and terminate its execution?

A). return

B). exit

C). break

D). continue

Which PHP feature allows defining functions with a variable number of arguments?

A). Optional parameters

B). Dynamic functions

C). Variable arguments

D). All of the above

Which keyword is used to define default parameter values in PHP functions?

A). default

B). var

C). const

D). None of the above

Which PHP keyword is used to define functions without specifying their names?

A). Dynamic functions

B). Anonymous functions

C). Inner functions

D). Nested functions

What will be the output of the following PHP code?
<?php
function greet() {
echo 'Hello, World!';
}
if (function_exists('greet')) {
greet();
} else {
echo 'Function does not exist';
}
?

A). Hello, World!

B). Function does not exist

C). Undefined function: greet

D). Function greet() { echo 'Hello, World!'; }

What will be the output of the following PHP code?
<?php
function sum($a, $b = 5) {
return $a + $b;
}
echo sum(3);
?

A). 3

B). 8

C). 5

D). Function call will result in an error

What is the significance of passing functions as arguments in PHP?

A). It allows functions to be called multiple times

B). It simplifies the function definition process

C). It enables dynamic function invocation and behavior

D). It prevents code duplication

What will be the output of the following PHP code?
<?php
function add($a, $b) {
return $a + $b;
}
$result = add(5, 3);
echo $result;
?

A). 8

B). add(5, 3)

C). function add($a, $b) { return $a + $b; }

D). $a + $b