[开发工具]我的第一个C++类

#include<iostream>

using namespace std;

class Sales_item{
public:
    double avg_price() const;
    bool same_isbn(const Sales_item &rhs) const
    {
        //this->units_sold = 99;
        return this->isbn == rhs.isbn;
    }
public:
   std::string isbn;
   unsigned units_sold;
   double revenue;

};

double Sales_item::avg_price() const{
   return (this->revenue / this->units_sold);
}
int main()
{
    Sales_item item1,item2;
    item1.isbn = "0-201-78345-X";
    item1.units_sold =10;
    item1.revenue = 300;

    item2.isbn = "0-201-78345-X";
    item2.units_sold = 2;
    item2.revenue = 70;

    if(item1.same_isbn(item2))
        cout<<"Same"<<endl;
    else
        cout<<"Different"<<endl;

    cout<<"item1:"<<item1.avg_price()<<endl;
    cout<<"item2:"<<item2.avg_price()<<endl;
    return 0;
}