1 files changed, 27 insertions, 0 deletions
diff --git a/oo/abstract.php b/oo/abstract.php
new file mode 100644
index 0000000..141f7b7
--- /dev/null
+++ b/oo/abstract.php
@@ -0,0 +1,27 @@
+<?php
+
+abstract class Polygon {
+    protected $sides = 0;
+    abstract protected function area();
+    public function getSidesNum() {
+        return $this->sides;
+    }
+}
+
+class Triangle extends Polygon {
+    private $width = 0;
+    private $height = 0;
+    function __construct($w, $h) {
+        /* parent::__construct(); perhaps abstract classes do not have a ctor */
+        $this->width = $w;
+        $this->height = $h;
+        $this->sides = 3;
+    }
+
+    public function area() {
+        return $this->width * $this->height * 1/2;
+    }
+}
+
+$rightTri = new Triangle(4,4);
+echo "area: {$rightTri->area()}, sides: {$rightTri->getSidesNum()}" . PHP_EOL;