小心php中的弱比较

switch.php

<?php

loose_comparison('github'); // github.com
strong_comparison('github'); // github.com

loose_comparison(0); // github.com
strong_comparison(0); // Oops! NSA...

function loose_comparison($str) {
    switch ($str) {
    case "github":
        echo "github.com\n";
        break;

    case "google":
        echo "google.com\n";

    default:
        echo "Oops! NSA...\n";
    }
}

function strong_comparison($str) {
    switch (strval($str)) {
    case "github":
        echo "github.com\n";
        break;

    case "google":
        echo "google.com\n";

    default:
        echo "Oops! NSA...\n";
    }
}