C++ //练习 14.2 为Sales_data编写重载的输入、输出、加法和复合赋值运算符。

C++ Primer（第5版）练习 14.2

练习 14.2 为Sales_data编写重载的输入、输出、加法和复合赋值运算符。

环境：Linux Ubuntu（云服务器）

工具：vim

代码块

/*************************************************************************> File Name: ex14.2.cpp> Author: > Mail: > Created Time: Mon 29 Apr 2024 08:08:50 AM CST************************************************************************/#include<iostream>
using namespace std;struct Sales_data{Sales_data(const string &s, unsigned n, double p):bookNo(s), units_sold(n), price(p), revenue(p * n) {}Sales_data(): Sales_data("", 0, 0) {}Sales_data(string s): Sales_data(s, 0, 0) {}friend istream &operator>>(istream &, Sales_data &);friend ostream &operator<<(ostream &, const Sales_data &);Sales_data& operator+= (Sales_data &);string isbn() const;Sales_data& combine(const Sales_data&);double avg_price() const;string bookNo;unsigned units_sold = 0;double price = 0.0;double revenue = 0.0;
};string Sales_data::isbn() const{return this->bookNo;
}Sales_data& Sales_data::combine(const Sales_data &rhs){units_sold += rhs.units_sold;revenue += rhs.revenue;price = rhs.price;bookNo = rhs.bookNo;return *this;
}double Sales_data::avg_price() const{if(units_sold){return revenue / units_sold;}else{return 0;}
}Sales_data& Sales_data::operator+= (Sales_data &sd){this->combine(sd);return *this;
}ostream &operator<<(ostream &output, const Sales_data &sd){output<<sd.bookNo<<" "<<sd.units_sold<<" "<<sd.price<<" "<<sd.revenue<<" "<<sd.avg_price()<<endl;return output;
}istream &operator>>(istream &input, Sales_data &sd){input>>sd.bookNo>>sd.units_sold>>sd.price;sd.revenue = sd.price * sd.units_sold;return input;
}int main(){Sales_data  book2, book4;cout<<"Enter book4: ";cin>>book4;book2 += book4;cout<<"Book2: "<<book2<<endl;return 0;
}