以下是一个使用PHP内制函数实现简单用户信息管理系统的实例：
```php
// 用户信息数组
$users = [
['id' => 1, 'name' => '张三', 'email' => 'zhangsan@example.com'],
['id' => 2, 'name' => '李四', 'email' => 'lisi@example.com'],
['id' => 3, 'name' => '王五', 'email' => 'wangwu@example.com']
];
// 添加用户信息
function addUser(&$users, $name, $email) {
$newUser = [
'id' => count($users) + 1,
'name' => $name,
'email' => $email
];
$users[] = $newUser;
}
// 删除用户信息
function deleteUser(&$users, $id) {
global $users;
foreach ($users as $key => $user) {
if ($user['id'] == $id) {
unset($users[$key]);
break;
}
}
}
// 更新用户信息
function updateUser(&$users, $id, $name, $email) {
foreach ($users as $key => $user) {
if ($user['id'] == $id) {
$users[$key]['name'] = $name;
$users[$key]['email'] = $email;
break;
}
}
}
// 获取用户信息
function getUser(&$users, $id) {
foreach ($users as $user) {
if ($user['id'] == $id) {
return $user;
}
}
return null;
}
// 显示用户信息
function displayUsers($users) {
echo "
