How to implement user registration and login for online question answering function

How to implement user registration and login for the online question answering function

In today's era of rapid development of the Internet, online answering questions has become a way for everyone to learn and entertain. To realize the function of online answering questions, you first need to have a user system, including user registration and login. This article describes how to implement these features using specific code examples.

1. Implementation of the user registration function

User registration means that users need to register their account before using the online question answering function. When users register, they need to enter some necessary information and verify the legitimacy of this information. The following is a simple sample code:

<?php
// 连接数据库
$connect = mysqli_connect("localhost", "username", "password", "database");

// 获取用户提交的注册信息
$username = $_POST['username'];
$password = $_POST['password'];
$email = $_POST['email'];

// 检查用户名是否已经存在
$query = "SELECT username FROM users WHERE username = '$username'";
$result = mysqli_query($connect, $query);
if (mysqli_num_rows($result) > 0) {
    echo "该用户名已被注册";
    exit;
}

// 插入用户信息到数据库
$query = "INSERT INTO users (username, password, email) VALUES ('$username', '$password', '$email')";
$result = mysqli_query($connect, $query);

if ($result) {
    echo "注册成功";
} else {
    echo "注册失败";
}

// 关闭数据库连接
mysqli_close($connect);
?>

2. Implementation of user login function

User login means that registered users log in by entering the correct user name and password. When the user logs in, it is necessary to check whether the user name and password entered by the user are correct, and after successful verification, the user information is saved in the session. The following is a simple sample code:

<?php
// 连接数据库
$connect = mysqli_connect("localhost", "username", "password", "database");

// 获取用户提交的登录信息
$username = $_POST['username'];
$password = $_POST['password'];

// 检查用户名和密码是否匹配
$query = "SELECT id, username FROM users WHERE username = '$username' AND password = '$password'";
$result = mysqli_query($connect, $query);
if (mysqli_num_rows($result) > 0) {
    // 将用户信息保存在会话中
    session_start();
    $_SESSION['loggedin'] = true;
    $_SESSION['username'] = $username;

    // 登录成功跳转到答题页面
    header("Location: quiz.php");
} else {
    echo "用户名或密码错误";
}

// 关闭数据库连接
mysqli_close($connect);
?>

The above is a simple sample code to implement the user registration and login functions. Of course, the real online question answering function may involve more details and functions, such as password encryption, verification codes, etc. These details can be further expanded and developed based on specific needs.

I hope this article can help you understand how to implement user registration and login for the online question answering function!

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