C++使用技巧：copy and swap idiom

Copy and Swap idiom

使用到著名的Big three中兩個特殊的成員函數（拷貝構造函數copy construction與賦值構造函數assignment constrcution）. 作用在于在深拷贝的过程中保证强异常的作用，具体代码如下

class Person
{
public:Person(int id, const char * pszName):_id(id), _pszName(new char[strlen(pszName) + 1]){strcpy(_pszName, pszName);}Person():_id(0){_pszName = new char[1];_pszName[0] = '\0';}~Person(){if (_pszName)delete _pszName;_pszName = nullptr;}int Id(void) const {return _id;}const char * Name(void) const {return _pszName;}Person(Person& rhs){_id = rhs._id;_pszName = new char[strlen(rhs._pszName) + 1];strcpy(_pszName, rhs._pszName);}Person& operator=(Person& rhs){Swap(rhs);return *this;}
private:void Swap(Person rhs){std::swap(_id, rhs._id);std::swap(_pszName, rhs._pszName);}
private:int _id;char * _pszName;
};