PHP | IntlChar::iscntrl() Function

The IntlChar::iscntrl() function is an inbuilt function in PHP which is used to check the given input is a control character or not. Control characters are line feed, tab, escape, etc. 

A control character is one of the following types: 

• ISO 8-bit control character (U+0000..U+001f and U+007f..U+009f)
• IntlChar::CHAR_CATEGORY_CONTROL_CHAR (Cc)
• IntlChar::CHAR_CATEGORY_FORMAT_CHAR (Cf)
• IntlChar::CHAR_CATEGORY_LINE_SEPARATOR (Zl)
• IntlChar::CHAR_CATEGORY_PARAGRAPH_SEPARATOR (Zp)

Syntax:

bool IntlChar::iscntrl( $codepoint )

Parameters: This function accepts single parameter $codepoint which is mandatory. The codepoint value is an integer values or character, which is encoded as a UTF-8 string.

Return Value: If $codepoint is a control character then it returns True, otherwise return False.

Below programs illustrate the IntlChar::iscntrl() function in PHP:

Program 1:

PHP

<?php
// PHP code to illustrate IntlChar::iscntrl()
// function

// Input data is character type
var_dump(IntlChar::iscntrl("G"));

// Input data is control character
var_dump(IntlChar::iscntrl("\n"));

// Input data is string type with control character
var_dump(IntlChar::iscntrl("G\n"));

// Input data is string type with no control character
var_dump(IntlChar::iscntrl("Geeksforgeeks"));

// Input data is number
var_dump(IntlChar::iscntrl("2018"));

// Input data is single digit
var_dump(IntlChar::iscntrl("5"));

?>

Output:

bool(false) 
bool(true) 
NULL 
NULL 
NULL 
bool(false) 

Note: If String and Numbers are used as a parameter then it returns NULL.

Program 2:

PHP

<?php
// PHP code to illustrate IntlChar::iscntrl()

// Declare an array $arr
$arr = array("G", "GeeksforGeeks", "^", "1001", "6", "\n",
                                             "\n\n", "\t");

// Loop run for every array element
foreach ($arr as $val){

    // Check each element as code point data
    var_dump(IntlChar::iscntrl($val));
}
?>

Output:

bool(false) 
NULL 
bool(false) 
NULL 
bool(false) 
bool(true) 
NULL 
bool(true) 

Reference: http://php.net/manual/en/intlchar.iscntrl.php