假设我有一个类X(X.h):classX{private:unsignedunitsSold=0;doublerevenue=0.0;public:doubleavgPrice();}avgPrice()应该怎么定义？Option1(类里面):X.hclassX{private:unsignedunitsSold=0;doublerevenue=0.0;public:doubleavgPrice(){returnunitsSold?revenue/unitsSold:0;}}Option2(在与类相同的文件中，但在类定义之外):X.hclassX{private:unsigneduni