??????const??inline??????#define

???????????ó????“??????????????????????”?????#define????????????????????????????????????????????????????

????#define ASPECT_RATIO 1.653

??????????????????????ASPECT_RATIO???????????????????????????????????????????????????ASPECT_RATIO????????????б??С?????漰?????????????????????????????????????????????????1.653????????ASPECT_RATIO?????ASPECT_RATIO???????????д???????ж???????????1.653?????????????????????????????????????????????????????У??????????????д????????????????????б??С?

??????????????????????????????????????????????


const double ASPECT_RATIO = 1.653;


???????????????Ч?????????????????????

??????????????????????е????????????????????????????У?????????????????????????????????????????const???????????????????????const?????磬????????ж??????????char*????????????????д????const??


const char * const authorName = "Scott Meyers";


????????const???????÷????????????????????????μ?????21??

?????????????????(class)???????????????????????????????????????У?????????????????????????????????????????????????????????????


class GamePlayer {
private:
 static const int NUM_TURNS = 5; // constant eclaration
 int scores[NUM_TURNS];  // use of constant
 ...
};


????????????????????????????????NUM_TURNS????????????????壬?????????????????????????ж?????????????????????????????????????????NUM_TURNS????????????????壬?????????????????????????ж?????????????


const int GamePlayer::NUM_TURNS; // mandatory definition;
  // goes in class impl.file


??????????????????С??????????????壬??????????????

??????????????????????????????????????????????????????????????????????????????????????????????磺int?? bool?? char ?????????????????

?????????????????????????￡??????????????????


class EngineeringConstants { // this goes in the class
private:  // header file
 static const double FUDGE_FACTOR;
 ...
};
 // this goes in the class implementation file
 const double EngineeringConstants::FUDGE_FACTOR = 1.35;


??????????????????????????????????????????????????????????????????????????GamePlayer::scores???????????????????б??????????????????С?????????????????Щ???????????????????????????????????????????????????ó???“????enum”?????????????????????????????????int???????????????????????????GamePlayer????????????????壺


class GamePlayer {
private:
 enum { NUM_TURNS = 5 } // "the enum hack" — makes
 // NUM_TURNS a symbolic name
 // for 5
 int scores[NUM_TURNS];// fine
};