2014-7-6 flyfish

在初始阶段会有大量数据增删改，而后期很少有更改，后期大部分是查询操作。

建立索引，使用排序的vector，使用二分法查找

以用户信息为例

用户信息包括，ID，名字，性别，手机号码

class CGender
{
public:
	enum 
	{
		Female=0,
		Male=1,		
		NotSpecified=2
	};
};


class CUser
{
public:
	UINT64 m_nID;
	CString m_strName;
	int m_nGender;
	UINT64 m_nPhoneNumber;

};

定义用户列表和索引

typedef std::pair<UINT64,std::shared_ptr<CUser>> USER;

建立针对用户操作的引擎

插入

根据ID查看是否存在该用户

根据ID查找用户

class CUserEngine
{
public:
	
	static std::vector<USER> m_vecUser;
	static void InsertUser(std::shared_ptr<CUser> p);
	static bool IsExist(UINT64 nID);
	static std::shared_ptr<CUser> QueryUserByID(UINT64 nID);

};

//小ID在前
bool UserIDSort (const USER& a, const USER& b) 
{ 
	return (a.first < b.first); 
}

void CUserEngine::InsertUser(std::shared_ptr<CUser> p)
{
	m_vecUser.push_back(USER(p->m_nID,p));
	std::sort(m_vecUser.begin(),m_vecUser.end(),UserIDSort);

}

struct UserIDCompare
{ 
	bool operator()(USER user, UINT64 nID) const
	{ 
		return user.first < nID; 
	}
	bool operator()(UINT64 nID, USER user) const
	{ 
		return nID < user.first;
	}
};

bool CUserEngine::IsExist(UINT64 nID)
{
	return std::binary_search(m_vecUser.begin(),m_vecUser.end(),nID,UserIDCompare());
}


std::shared_ptr<CUser> CUserEngine::QueryUserByID(UINT64 nID)
{
	std::shared_ptr<CUser>p=nullptr;

	std::vector<USER>::iterator iter=std::lower_bound(m_vecUser.begin(),m_vecUser.end(),nID,UserIDCompare());
	if (iter!=m_vecUser.end() && !(UserIDCompare()(nID,*iter)))
	{
		p=(*iter).second;
	}
	return p;

}

//随机生成用户信息
std::default_random_engine dre;
std::uniform_int_distribution<int> diGender(CGender::Female,CGender::NotSpecified);
std::uniform_int_distribution<UINT64> diPhoneNUmber(10000000000,19999999999);


for (int i=1;i<10;i++)
{
	std::shared_ptr<CUser> p(new CUser());
	p->m_nID=i;
	p->m_nGender=diGender(dre);
	p->m_nPhoneNumber=diPhoneNUmber(dre);
	CUserEngine::InsertUser(p);
}
for each(auto e in CUserEngine::m_vecUser)
{
	//输出用户信息
}

if(CUserEngine::IsExist(5))
{
	//查找是否存在ID为5的用户
}
std::shared_ptr<CUser> p=CUserEngine::QueryUserByID(3);
if (nullptr!=p)
{
	//输入ID为3的用户信息
}