พี่ๆคะ ถามหน่อย...คือ อยากทราบว่า การเขียนแบบ OOP กับการเขียน Function ต่างกันอย่างไรเหรอคะ

<?php
class human {
var $name = “human”;// default name = “human”
var $sex = 1; // default = 1 and 1 = male, 2 = female
var $height = 0; // height > 0
var $weight = 0; // weight > 0
var $age = 0; // age > 0
function showName(){
return $this->name;
}
function showSex(){
return $this->sex;
}
function showHeight(){
return $this->height;
}
function showWeight(){
return ($this->sex == 2 ? 'No Answer' : $this->weight);
}
function showAge(){
return ($this->sex == 2 ? 'No Answer' : $this->age);
}
}
$somsak = new human();
$somsak->name = 'Somsak';
$somsak->sex = 1;
$somsak->height = 178;
$somsak->weight = 65;
$somsak->age = 28;
echo 'Name : '.$somsak->showName().'<br />';
echo 'Sex : '.$somsak->showSex().'<br />';
echo 'Height : '.$somsak->showHeight().'<br />';
echo 'Weight : '.$somsak->showWeight().'<br />';
echo 'Age : '.$somsak->showAge().'<br />';
$somying = new human();
$somying->name = 'Somying';
$somying->sex = 2;
$somying->height = 168;
$somying->weight = 48;
$somying->age = 25;
echo 'Name : '.$somying->showName().'<br />';
echo 'Sex : '.$somying->showSex().'<br />';
echo 'Height : '.$somying->showHeight().'<br />';
echo 'Weight : '.$somying->showWeight().'<br />';
echo 'Age : '.$somying->showAge().'<br />';
?>