プログラム作成（calendar.php：カレンダー生成）

php/php10/day03-3/calendar.php

+<?php
+if ($_GET['num']=='') {
+    $today_year =date("Y");
+    $today_month=date("n");
+} else {
+    $timestamp=mktime(0, 0, 0, date("n") + $_GET['num'],
+            date("d"), date("Y"));
+    $today_year = date("Y", $timestamp);
+    $today_month =date("n", $timestamp);
+}
+$current = mktime(0, 0, 0, $today_month, 1, $today_year);
+$first_day =date("w",$current);
+$last_day = date("t",$current);
+?>
+<html>
+<body>
+<h1 style = "background:#cccccc">
+<?php print(date("Y年m月", $current)); ?>
+    のカレンダ</h1>
+<table border="1" width="300">
+<tr>
+  <th>日</th><th>月</th><th>火</th><th>水</th>
+  <th>木</th><th>金</th><th>土</th>
+</tr>
+<?php
+for ($i = 1; $i <= first_day + $last_day; $i++) {
+    if ($i % 7 == 1) {print ("<tr>");}
+    if($i > $first_day) {
+        print("<td>".($i-first)."</td>");
+    } else {
+        print("<td> & nbsp;</td>");
+    }
+    if ($i % 7 == 0) {print("</tr>"); }
+}
+?>
+</table>
+</body>
+</html>
+