String Concatenation in PHP

<?php
    $x = 'Rakib'; //variable x holds my name Rakib
    $y = 'Sami'; //variable y holds my friends name Sami
    echo $x.' '.$y; //printing the name of my name & my friends name
?>

String in PHP

<?php
    $x = 'Rakib'; //variable x holds my name Rakib
    echo $x; //printing my name
?>

Variable decleration in PHP

<?php
    $x = 1; //variable x holds 1
    $y = 7; //variable y holds 7
    $res = $x + $y; //variable res holds the addition of x and y
    echo $res; //printing the result
?>

Hello World in PHP

<?php
    echo 'Hello World';
?>