假设我有这样的类(class):publicclassCar{privatedoubledistanceDriven;publicvoiddrive(doublemiles){distanceDriven+=miles;}publicvoiddriveInCanada(doublekilometer){distanceDriven+=convertToMiles(kilometer);}privatedoubleconvertToMiles(doublekm){returnkm*0.621371192;}}可以看到convertToMiles是:不使用任何实例变量只在类内使用应该声明为
