定义

class CDefaultSetting
{
protected:
	CDefaultSetting() {}
	~CDefaultSetting() {}

public:
	static CDefaultSetting& GetInstance()
	{
		static CDefaultSetting instance;
		return instance;
	}

public:
	int m_nTest = 0;
};

使用

CDefaultSetting::GetInstance().m_nTest = 1;