istream::operator >>
istream& operator >>( char* psz );

istream& operator >>( unsigned char* pusz );

istream& operator >>( signed char* pssz );

istream& operator >>( char& rch );

istream& operator >>( unsigned char& ruch );

istream& operator >>( signed char& rsch );

istream& operator >>( short& s );

istream& operator >>( unsigned short& us );

istream& operator >>( int& n );

istream& operator >>( unsigned int& un );

istream& operator >>( long& l );

istream& operator >>( unsigned long& ul );

istream& operator >>( float& f );

istream& operator >>( double& d );

istream& operator >>( long double& ld ); (16-bit only)

istream& operator >>( streambuf* psb );

istream& operator >>( istream& (*fcn)(istream&) );

istream& operator >>( ios& (*fcn)(ios&) );

這些是本來>>支持的類型。
對于cin來說,如cin>>(int)a，而輸入一字符串，則會(huì)使cin陷入錯(cuò)誤狀態(tài)，故在輸入之前應(yīng)該先檢查if（isdigit（a））。