strtotime时间的处理

?php
    /**
     * @company xingquan
     * @auther        BianJiang
     * @date     Mon Mar 03 11:03:15 CST 2008
     * @copyright     Shen Yang Xing Quan
     * @todo 计算指定日期后5天的日期
     * @desc        strtotime将任何英文文本的日期时间描述解析为 Unix 时间戳
     *                 strtotime处理日期相关的任务非常实用与灵活
    */
    $timestamp = mktime(0, 0, 0, 3, 3, 2008);
    //在当前的时间戳
    $tomorrow = strtotime("+1days", $timestamp);
    $yesterday = strtotime("-1days", $timestamp);
    $nextWeek = strtotime("+1weeks", $timestamp);
    $nextMonth = strtotime("+1month", $timestamp);
    $nextYear = strtotime("+1year", $timestamp);
    echo date("Y-m-d", $timestamp) . "\n";
    echo "明天的时间是：" . date("Y-m-d", $tomorrow)."\n";
    echo "昨天的时间是：" . date("Y-m-d", $yesterday)."\n";
    echo "下周的时间是：" . date("Y-m-d", $nextWeek)."\n";
    echo "下月的时间是：" . date("Y-m-d", $nextMonth)."\n";
    echo "明年的时间是：" . date("Y-m-d", $nextYear)."\n";
    //++++++++++++++++++++++++++++++++++++++++++++++++++
    /**
     * @todo 时间差计算
     * */
    $startDate = mktime(0, 0, 0, 2, 1, 2008);
    $endDate = mktime(0, 0, 0, 3, 1, 2008);
    $days = round(($endDate - $startDate)/3600/24);
    echo $days;
?>