Functions — Part 1 MCQs with Explanations

Type hinting gives you the ability to force parameters to be objects of certain class or to be arrays. PHP 5 introduced this feature.

When you pass an argument in the above manner or say we pass 15 and 3 directly, it is called passing by value or call by value.

You can designate certain arguments as optional by placing them at the end of the list and assigning them a default value of nothing.

Except a) others are invalid names. According to the specified regular expression ([a-zA-Z_x7f-xff][a-zA-Z0-9_x7f-xff]*), a function name like this one is valid.

This will be the output- I am a Fatal error: Cannot redeclare b()

This will be the output- Fatal error: Call to undefined function b(). You cannot call a function which is inside a function without calling the outside function.

The correct answer is Option B: Error Here's why: In PHP, variables defined outside of a function are not automatically accessible inside the function. Scope is a crucial concept in programming. The variable `$op2` is defined outside the function `foo()`. Inside `foo()`, you are trying to use `$op2` without it being defined within the function's scope. Therefore, PHP will throw an error (specifically, a notice about an undefined variable) when trying to access `$op2` within the function. Although the `echo $op1` will work fine , but after that when trying to access the `$op2` that is not defined inside the function scope it will throw error . To make `$op2` accessible inside the function, you would need to either: 1. Pass it as an argument to the function. 2. Use the `global` keyword to bring it into the function's scope . Since neither of these is done in the given code, an error occurs.

Option A: Magic Function In PHP, a function that starts with double underscores (__) is known as a magic function . These functions are predefined in PHP and are automatically called when certain events or operations occur. Examples include __construct, __destruct, __get, __set, and many others, which are automatically invoked when specific conditions are met in the code. Option B: Inbuilt Function Inbuilt functions in PHP are built into the language and are not necessarily prefixed with double underscores. They are regular functions like echo(), print(), and other standard PHP functions, but do not follow the magic function naming convention. Option C: Default Function There is no specific category called "default function" in PHP. This term is not commonly used in the context of PHP function naming or functionality. Option D: User Defined Function User-defined functions are those created by the developer, and they do not follow the double underscore convention. These functions are typically defined with a name chosen by the user and are not prefixed with any special characters like the magic functions. Conclusion: The correct answer is Option A: Magic Function . Magic functions in PHP start with double underscores and are automatically invoked by PHP under certain conditions.

It is possible to call a function using a variable which stores the function name.

Here is an example- <?php function foo () { $args = func_get_args() ; foreach ( $args as $k => $v ) { echo "arg" .( $k + 1 ). ": $vn" ; } } foo () ; /* will print nothing */ foo ( "Hello" ) ; /* will print Hello */ foo ( "Hello" , "World" , "Bye" ) ; /* will print Hello World Bye */ ?>

Here is an example- // get all php files AND txt files $files = glob( '*.{php,txt}' , GLOB_BRACE ) ; print_r( $files ) ; /* output looks like: Array ( [0] => phptest.php [1] => pi.php [2] => post_output.php . . . )

We can use the memory_get_usage() function, and to get the highest amount of memory used at any point, we can use the memory_get_peak_usage() function.

Many people use the md5() function for this, even though it’s not exactly meant for this purpose. uniqueid() is the function that is to be used.

We will be able to achieve almost 50% size reduction using this function. The gzuncompress() function is used to uncompress the string.

The chr() function returns a character from the specified ASCII value. Since the ASCII value of 4 is 52, thus 4 was displayed.

The ord() function returns the ASCII value of the first character of a string. The ASCII value of h is 104, thus 104 was displayed.

The wordwrap() function wraps a string into new lines when it reaches a specific length.

The atan() function returns the arc tangent of arg as a numeric value between -Pi/2 and Pi/2 radians.

The define() function defines a constant.

The defined() function checks whether a constant exists.

It is possible to call a function using a variable which stores the function name also the chr() function returns a character from the specified ASCII value.

cos() gives the cos value of the argument. Here the function returns 1.

imple order of execution.

Functions returns value 30.

It is possible to assign function names as strings to variables and then treat these variables exactly as you would the function name itself.

Two is declared in one and is called after one.Hence it works.

Donkey starts from position 4 in string.

Using the define function to define the constant “const”.

The hex2bin() function converts a string of hexadecimal values to ASCII characters.

The addslashes() function returns a string with backslashes in front of predefined characters.

The explode() function breaks a string into an array.

The strtr() function translates certain characters in a string.

The stripos() function finds the position of the first occurrence of a string inside another string.

The switch statement is executed with $x = 9.

b is undeclared if TV() is not called first.

This one works because b is declared independent of TV() also.

Function b is declared twice.

b is declared as TV() is executed first.

Function does not return anything.

Function returns $total.