Task 03 Article Parser, PHP Basic Exam 29 July Morning

<?php
// Overview: Find the regular expr. (preg_replace_callback)  => func. "articles" => $match1=topic; $match2=author; $realMonth=month; $print=article summary
$text=$_GET['text'];

function articles($matches){
// $print contains article summary
    if (strlen($matches[4])>100){
        $str=substr((trim($matches[4])),0,100);
        $print=htmlspecialchars($str)."...";
    }else{
        $print=htmlspecialchars(trim($matches[4]))."...";
    }
//$month contains month number as str
    $month=substr(($matches[3]),3,2);
// switch-case for the month's name
    switch ($month){
        case "01":
            $realMonth="January";
            break;
        case "02":
            $realMonth="February";
            break;
        case "03":
            $realMonth="March";
            break;
        case "04":
            $realMonth="April";
            break;
        case "05":
            $realMonth="May";
            break;
        case "06":
            $realMonth="June";
            break;
        case "07":
            $realMonth="July";
            break;
        case "08":
            $realMonth="August";
            break;
        case "09":
            $realMonth="September";
            break;
        case "10":
            $realMonth="October";
            break;
        case"11":
            $realMonth="November";
            break;
        case "12":
            $realMonth="December";
            break;
    }
//$match1 - topic
    $match1=htmlspecialchars(trim($matches[1]));
//$match2 - author
$match2=htmlspecialchars(trim($matches[2]));

    echo "<div>"."\n"."<b>Topic:</b> <span>$match1</span>\n"."<b>Author:</b> <span>$match2</span>\n"."<b>When:</b> <span>$realMonth</span>\n"."<b>Summary:</b> <span>$print</span>\n</div>\n";
}

//every time when finds the regular expr. will perform "article" function above
 preg_replace_callback(
    '/(.+?)[%](.+?)[ ;](\d{2}-\d{2}-\d{4})[ -]((.+?)*)/',"articles",$text
);?>