C++ //练习 7.11 在你的Sales_data类中添加构造函数，然后编写一段程序令其用到每个构造函数。-编程知识

C++ //练习 7.11 在你的Sales_data类中添加构造函数，然后编写一段程序令其用到每个构造函数。

C++ Primer（第5版）练习 7.11

练习 7.11 在你的Sales_data类中添加构造函数，然后编写一段程序令其用到每个构造函数。

环境：Linux Ubuntu（云服务器）

工具：vim

代码块

/*************************************************************************> File Name: ex7.11.cpp> Author: > Mail: > Created Time: Thu 15 Feb 2024 12:26:50 PM CST************************************************************************/#include<iostream>
using namespace std;struct Sales_data{Sales_data() = default;Sales_data(const string &s): bookNo(s) {}Sales_data(const string &s, unsigned n, double p):bookNo(s), units_sold(n), price(p), revenue(p * n) {}Sales_data(istream &);friend ostream &print(ostream&, const Sales_data&);friend istream &read(istream&, 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;
};Sales_data::Sales_data(istream &in){read(in, *this);
}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;return *this;
}double Sales_data::avg_price() const{if(units_sold){return revenue / units_sold;}else{return 0;}
}Sales_data add(const Sales_data &sd1, const Sales_data &sd2){Sales_data t = sd1;t.combine(sd2);return t;
}ostream &print(ostream &output, const Sales_data &sd){output<<sd.bookNo<<" "<<sd.units_sold<<" "<<sd.price<<" "<<sd.revenue<<" "<<sd.avg_preturn output;
}istream &read(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 book1("0-201-78345-X", 10, 20.0);Sales_data book2("0-301-77649-Y");print(cout, book1);print(cout, book2);return 0;
}