<?php
session_start();
 $upd=$_GET['upd'];
 $id=$_GET['id'];
 $order=$_SESSION['cart'];
 foreach($order as $key=>$value){
	 if($value['id']==$id){
		 switch($upd){
			 case 0:
			 if($value['num']>1){
				 $order[$key]['num']-=1;
			 }else{
				 unset($order[$key]);
			 }
			 break;
			 case 1:
			 $order[$key]['num']+=1;
			 break;
			 default;
		 }
		 header("location:cart.php");
	 }
	 if($upd==""){
		 $sum += $value['price']*$value['num'];
		 header("location:order.php");
	 }
 }
 $_SESSION['num']=array_sum(array_column($order,"num"));
 $_SESSION['sum']=$sum;
 $_SESSION['cart']=$order;
?>