php - 固定货币值(value)为负-6ren

php - 固定货币值(value)为负

转载作者：行者123 更新时间：2023-11-29 07:24:28

我用 php 制作了一个游戏，人们可以在其中升级他们的东西，钱将从他们的帐户中扣除。但当货币值(value)变低时，它就会变成负值，元素就会升级。这是代码:

<?php
session_start();
include_once 'dbconnect.php';
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "dbtest";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
} 

if(!isset($_SESSION['user']))
{
header("Location: index.php");
}
?>
</html>
<head>
<body bgcolor="black">
<?php echo "<font color=\"#49fb35\" size=\"5\">Update Firewall Software $300</font><br>"; ?>
<a href="firewall.php"><font color="#49fb35" size="5">Upgrade Firewall.exe for $300</font></a>
</head>
</html>

货币值(value)低时如何停止升级？

最佳答案

您可以使用 PHP 来验证该值是否大于 0，方法是:

$query1 = "SELECT * from users WHERE user_id=".$_SESSION['user'];
$result = mysql_query($query1);

while($row = mysql_fetch_array($result)) {
    // Get money from column
    $money = $row['money'];
}

if($money >= 300) {

$query = "UPDATE users SET firewall = firewall + 1, money = money - 300 WHERE user_id=".$_SESSION['user'];

$update = mysqli_query($conn,$query);

} else {

// Prints error
echo 'Money is not enough to upgrade';

}