Heredoc string function act just like quoted strings but it starts with <<< followed by an identifier and begins with the new line ,then the set of strings and finally ends with the same identifier and finally semi semicolon .
Example :
<?php
$name = “example”;
$str = <<<EOD
This is an heredoc $name
with php interview questions
Answers.
EOD;
echo $str;
?>
Output :
This is an heredoc example with php interview questions Answers.
Note : Here from above example , EOD is an an identifier , and there should not be whitespace located at end of a line, without any other characters following it.
Nowdoc :
Nowdoc is similar to heredoc , variables are not accepted in Nowdoc just like single quote , whwrre as heredoc accepts the variables .
Example :
<?php
$name = “example”;
$str = <<<EOD
This is an nowdoc $name
with php interview questions
Answers.
EOD;
echo $str;
?>
Output :
This is an nowdoc $name with php interview questions Answers.
To know about single quote and double quote please click this link