String Concatenation in PHP

For string addition (concatenation) the dot operator is used:

<?php
	$str = 'abc' . 'def'; // add two strings
	echo $str;            // will output 'abcdef'
?>

Strings can also be stored in variables:

<?php
	$str1 = 'abc';
	$str2 = 'def';
	echo $str1 . $str2; // will output 'abcdef'
?>

You can also add variables and strings:

<?php
	$str1 = 'abc';
	$str2 = 'def';
	echo $str1 . '!!!' . $str2; // will output 'abc!!!def'
?>

Create a variable $str and assign it the string 'hello'. Output the value of this variable to the screen.

Create a variable with the text 'abc' and a variable with the text 'def'. Using these variables and the string concatenation operation, output the string 'abcdef' to the screen.