推三返一模式系统开发可以按照以下步骤进行：
This article is only for system development requirements reference
设计系统架构：根据需求，设计系统的架构。决定需要使用哪种技术栈和开发框架，比如前端可以选择使用小程序开发框架，后端可以选择使用某种编程语言和数据库来实现系统功能。以下是推三返一模式系统开发代码示例
<?php
class DirectSalesSystem {
private $members = [];
public function addMember($name, $sponsor) {
$member = ['name' => $name, 'sponsor' => $sponsor];
$this->members[] = $member;
}
public function getDownline($memberIndex) {
$member = $this->members[$memberIndex];
$downline = [];
foreach ($this->members as $key => $m) {
if ($m['sponsor'] == $member['name']) {
$downline[] = $key;
}
}
return $downline;
}
public function getUpline($memberIndex) {
$member = $this->members[$memberIndex];
$upline = [];
foreach ($this->members as $key => $m) {
if ($m['name'] == $member['sponsor']) {
$upline[] = $key;
}
}
return $upline;
}
}
