C++ Primer 第12章 习题12.8

//习题12.8//将Sales_item::avg_price定义为内联函数//有三种方式//方式一：将函数的定义写在类定义体内部。class Sales_item{public:double Sales_item::avg_price() const{if(unite_sold)return revenue/unite_sold;elsereturn 0;}//....其他成员函数省略private:std::string isbn;unsighed unite_sold;double revenue;};//方式二：在类定义体内部的函数声明上用inline显式指定class Sales_item{public:inline double Sales_item::avg_price() const;//...其他成员函数private:std::string isbn;unsigned units_sold;double revenue;};//....avg_price的定义略//方式三：在类定义体外部的函数定义用inline显式指定class Sales_item{public:double Sales_item::avg_price() const;//....其他成员函数略private:std::string isbn;unsigned unite_sold;double revenue;};inline double Sales_item::avg_price()const{if(unite_sold)return revenue/units_sold;else return 0;}