The ctype_cntrl() is an inbuilt function in PHP which is used to check all the characters in string/text are control characters. Control characters are e.g. line feed, tab, escape.
Syntax:
bool ctype_cntrl ( $str )
Parameters: This function accepts a single parameter $str. It is a mandatory parameter which specifies the string.
Return Value: It returns True if a string contains only control characters and False on failure.
Examples:
Input: GeeksforGeeks Output: No Explanation: String (GeeksforGeeks) contains only the alphanumeric characters. Input: \n\t Output: Yes Explanation: String (\n\t) contains only the control character.
Below programs illustrate the ctype_cntrl() function.
Program 1:
<?php // PHP program to check if a string has all // control characters $str1 = "GeeksforGeeks" ;
if ( ctype_cntrl( $str1 ))
echo "Yes\n" ;
else
echo "No\n" ;
$str2 = "\n\t" ;
if ( ctype_cntrl( $str2 ))
echo "Yes\n" ;
else
echo "No\n" ;
?> |
No Yes
Program 2: Implementation of ctype_cntrl() function which takes input of an array of string that contains integers and special Symbol.
<?php // PHP program to check if a string has all // control characters $str = array (
"Geeks" ,
"Geeks space" ,
"@@##-- /" ,
"\n" ,
"\t \r" ,
"\r\t\n"
); // Check the above strings by using // ctype_cntrl() function foreach ( $str as $test ) {
if (ctype_cntrl( $test ))
echo "Yes\n" ;
else
echo "No\n" ;
} ?> |
No No No Yes No Yes
References: http://php.net/manual/en/function.ctype-cntrl.php