Question

我的PHP代码存在一些问题。我对变量'$ total'有一个未定义的索引错误。我需要一些帮助来解决这个问题。这是我的整个PHP代码。

<?php
include('inc/connect.php');
session_start();
?>
<html>
<head>
    <title>Cart</title>
    <link rel='stylesheet' href='css/main.css' />
</head>
<body>
    <?php
    $page = 'index.php';

    if(isset($_GET['add'])){
        $add_id = $_GET['add'];
        $quantity = mysql_query("SELECT id, quantity FROM products WHERE id='$add_id'");
        while($quantity_row = mysql_fetch_assoc($quantity)){
            if($quantity_row['quantity'] !=@$_SESSION['cart_'.$add_id]){
                @$_SESSION['cart_'.$_GET['add']]+='1';
                header('Location: index.php');
            }
            else{
                header('Location: index.php?err=max');
            }
        }

    }

    if(isset($_GET['remove'])){
        $_SESSION['cart_'.(int)$_GET['remove']]--;
        header("Location: index.php");
    }

    if(isset($_GET['delete'])){
        $_SESSION['cart_'.(int)$_GET['delete']]='0';
        header('Location: index.php');
    }

    function products(){
        $get = mysql_query("SELECT id, name, description, price FROM products WHERE quantity > 0 ORDER BY id DESC");
        if(mysql_num_rows($get) == 0){
            echo "There are no products to display.";
        }
        else{
            while($get_row = mysql_fetch_assoc($get)){
                echo '<p>'.$get_row['name'].'<br />'.$get_row['description'].'<br />$'.$get_row['price'].' <a href="cart.php?add='.$get_row['id'].'">Add</a></p>';
            }
        }
    }

    function cart(){
        foreach($_SESSION as $name => $value){
            if($value>0){
                if(substr($name, 0, 5)=='cart_'){
                    $id = substr($name, 5, strlen($name)-5);
                    $get = mysql_query("SELECT id, name, price FROM products WHERE id='$id'");
                    while($get_row = mysql_fetch_assoc($get)){
                        $sub = $get_row['price']*$value;
                        echo $get_row['name'].' x '.$value.' @ $'.number_format($get_row['price'], 2).' = $'.$sub.' <a href="cart.php?add='.$id.'">[+]</a> <a href="cart.php?remove='.$id.'">[-]</a> <a href="cart.php?delete='.$id.'">[Delete]</a>';
                    }
                }
                $total += $sub; 
            }
        }
        echo '<br />'.$total;
    }

    ?>
</body>

在此先感谢您的帮助。在不久的将来，我可能需要更多的帮助。

Answer 1

代码第一次尝试执行$total+=$sub时，$total未定义。

您需要在$total功能的顶部设置cart()：

function cart(){
    $total = 0;
    /// rest of code
}

Answer 2

在您的功能购物车（）中：

首先声明变量$total。

例如$total = 0 ; 然后开始递增它$total += $sub ;

Answer 3

<?php
include('inc/connect.php');
session_start();
?>
<html>
<head>
    <title>Cart</title>
    <link rel='stylesheet' href='css/main.css' />
</head>
<body>
    <?php
    $page = 'index.php';

    if(isset($_GET['add'])){
        $add_id = $_GET['add'];
        $quantity = mysql_query("SELECT id, quantity FROM products WHERE id='$add_id'");
        while($quantity_row = mysql_fetch_assoc($quantity)){
            if($quantity_row['quantity'] !=@$_SESSION['cart_'.$add_id]){
                @$_SESSION['cart_'.$_GET['add']]+='1';
                header('Location: index.php');
            }
            else{
                header('Location: index.php?err=max');
            }
        }

    }

    if(isset($_GET['remove'])){
        $_SESSION['cart_'.(int)$_GET['remove']]--;
        header("Location: index.php");
    }

    if(isset($_GET['delete'])){
        $_SESSION['cart_'.(int)$_GET['delete']]='0';
        header('Location: index.php');
    }

    function products(){
        $get = mysql_query("SELECT id, name, description, price FROM products WHERE quantity > 0 ORDER BY id DESC");
        if(mysql_num_rows($get) == 0){
            echo "There are no products to display.";
        }
        else{
            while($get_row = mysql_fetch_assoc($get)){
                echo '<p>'.$get_row['name'].'<br />'.$get_row['description'].'<br />$'.$get_row['price'].' <a href="cart.php?add='.$get_row['id'].'">Add</a></p>';
            }
        }
    }

    function cart(){
    $total = 0;
        foreach($_SESSION as $name => $value){
            if($value>0){
                if(substr($name, 0, 5)=='cart_'){
                    $id = substr($name, 5, strlen($name)-5);
                    $get = mysql_query("SELECT id, name, price FROM products WHERE id='$id'");
                    while($get_row = mysql_fetch_assoc($get)){
                        $sub = $get_row['price']*$value;
                        echo $get_row['name'].' x '.$value.' @ $'.number_format($get_row['price'], 2).' = $'.$sub.' <a href="cart.php?add='.$id.'">[+]</a> <a href="cart.php?remove='.$id.'">[-]</a> <a href="cart.php?delete='.$id.'">[Delete]</a>';
                    }
                }
                $total += $sub; 
            }
        }
        echo '<br />'.$total;
    }

    ?>
</body>

为您修复了代码。

PHP代码中未定义的索引？

3 个答案: