PHP 整数

<?php
    $x=123;
    echo $x;
?>

<?php
    $a=100;
    var_dump($a);
?>

<?php 
    // decimal base integers 
    $deci1 = 40;  
    $deci2 = 500;  
   // octal base integers 
    $octal1 = 07;  
   // hexadecimal base integers 
    $octal = 0x45;  
    $add = $deci1 + $deci2; 
    echo $add; 
?>