php 繼承（擴充） （有錯，待修改）

<?php
    class Animal{
        var $_weight;

         function __construct($weight){
            echo "正在構造動物……/n";
            $this->weight = $weight;
        }

         function claim(){
            echo "我是動物/n";
        }

         function display(){
            echo "動物->/n";
            echo "重量為：$this->_weight 千克/n";
        }
    }

    class Cattle extends Animal{
         var $_hornLength;

         function __construct($weight, $hornLength){
            ehco "正在構造牛……/n";
            $this->_weight     = $weight;
            $this->_hornLength = $hornLength;
        }

         function display(){
            echo "牛->/n";
            echo "重量為：$this->_weight 千克/n";
            ehco "角長為：$this->_hornLength 厘米/n";
        }
    }

    $chick = new Animal(1.2);
    $chick->claim();
    $chick->display();

    $cattle = new Cattle(120, 23);
    $cattle->claim();
    $cattle->display();

?>