如何将变量作为构造函数参数或函数参数传递

我正在阅读有关使用变体实现状态机的信息。我尝试创建一个采用变体参数来初始化状态的构造。但是，当定义构造函数时，我会收到一条警告，指出这被识别为函数声明。

此外，当我尝试为状态定义一个setter时，当尝试调用它时会产生编译器错误

这是代码

#include "pch.h"
#include <iostream>
#include <variant>
#include <cassert>
struct DoorState
{
    struct DoorOpened {};
    struct DoorClosed {};
    struct DoorLocked {};
    using State = std::variant<DoorOpened, DoorClosed, DoorLocked>;
    DoorState()
    {
    }
    DoorState(State & state)
    {
        m_state = state;
    }
    void open()
    {
        m_state = std::visit(OpenEvent{}, m_state);
    }
    void close()
    {
        m_state = std::visit(CloseEvent{}, m_state);
    }
    void lock()
    {
        m_state = std::visit(LockEvent{}, m_state);
    }
    void unlock()
    {
        m_state = std::visit(UnlockEvent{}, m_state);
    }
    struct OpenEvent
    {
        State operator()(const DoorOpened&) { return DoorOpened(); }
        State operator()(const DoorClosed&) { return DoorOpened(); }
        // cannot open locked doors
        State operator()(const DoorLocked&) { return DoorLocked(); }
    };
    struct CloseEvent
    {
        State operator()(const DoorOpened&) { return DoorClosed(); }
        State operator()(const DoorClosed&) { return DoorClosed(); }
        State operator()(const DoorLocked&) { return DoorLocked(); }
    };
    struct LockEvent
    {
        // cannot lock opened doors
        State operator()(const DoorOpened&) 
        { 
            std::cout << "DoorOpened" << std::endl;
            return DoorOpened(); 
        }
        State operator()(const DoorClosed&) { return DoorLocked(); }
        State operator()(const DoorLocked&) { return DoorLocked(); }
    };
    struct UnlockEvent
    {
        // cannot unlock opened doors
        State operator()(const DoorOpened&) { return DoorOpened(); }
        State operator()(const DoorClosed&) { return DoorClosed(); }
        // unlock
        State operator()(const DoorLocked&) { return DoorClosed(); }
    };
    void set(State state)
    {
    }
    State m_state;
};
int main()
{
    //DoorState s(DoorState::DoorOpened);
    DoorState s; 
    s.set(DoorState::DoorOpened);
    s.lock();
    return 0;
}