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4108f6c42d
- 新增现代 C++ 教程的 Preface 章节，包括英文和中文版本 - 添加 C++ Primer 练习代码 - 新增 Learn C++ 教程的 C++ 开发简介章节 - 添加头文件解析文档 - 更新 mkdocs.yml，包含新教程的目录结构 - 修改项目设置，使用 Python 3.10环境
73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
//
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// Created by ChenYL on 2022/5/14.
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//
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#ifndef PAT_SALES_DATA_H
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#define PAT_SALES_DATA_H
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# include <iostream>
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# include <string>
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class Sales_data {
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friend std::istream& operator >> (std::istream&, Sales_data&);
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friend std::ostream& operator >> (std::ostream&, const Sales_data&);
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friend bool operator < (const Sales_data&, const Sales_data&);
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friend bool operator == (const Sales_data&, const Sales_data&);
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public:
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Sales_data() = default;
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Sales_data(const std::string &book):bookNo(book) { }
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Sales_data(std::istream &is) {is >> *this;}
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public:
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Sales_data& operator += (const Sales_data&);
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std::string isbn() const { return bookNo;}
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private:
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std::string bookNo; //书籍编号
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unsigned units_sold = 0; //销售量
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double selling_price = 0.0; //原始价格
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double sale_price =0.0; //市售价格
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double discount = 0.0; //折扣
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};
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inline bool compareIsbn(const Sales_data &lhs, const Sales_data &rhs) {
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return lhs.isbn() == rhs.isbn();
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}
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inline bool operator !=(const Sales_data &lhs, const Sales_data &rhs) {
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return !(lhs == rhs); //基于运算符==给出!=的定义
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}
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Sales_data& Sales_data::operator+=(const Sales_data& rhs) {
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units_sold += rhs.units_sold;
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sale_price = (rhs.sale_price * rhs.units_sold + sale_price * units_sold) / (rhs.units_sold + units_sold);
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if (selling_price != 0)
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discount = sale_price / selling_price;
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return *this;
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}
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Sales_data operator + (const Sales_data &lhs, const Sales_data &rhs)
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{
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Sales_data ret(lhs);//把hs的内容拷贝到临时变量ret中，这种做法便于运算
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ret += rhs; //把rhs的内容加入其中
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return ret; //返回ret
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}
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std::istream& operator >> (std::istream& in, Sales_data& s) {
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in >> s.bookNo >> s.units_sold >> s.selling_price >> s.sale_price;
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if (in && s.selling_price != 0)
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s.discount = s.sale_price / s.selling_price;
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else
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s = Sales_data();//输入错误，重置输入的数据
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return in;
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}
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std::ostream& operator << (std::ostream& out,const Sales_data& s)
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{
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out << s.isbn();
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// out << s.isbn() <<" " << s.units_sold << " "<< s.selling_price <<""<< s.sale_price <<""<< s.discount;
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return out;
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}
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#endif //PAT_SALES_DATA_H
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