/*
* This file contains code from "C++ Primer, Fifth Edition", by Stanley B.
* Lippman, Josee Lajoie, and Barbara E. Moo, and is covered under the
* copyright and warranty notices given in that book:
*
* "Copyright (c) 2013 by Objectwrite, Inc., Josee Lajoie, and Barbara E. Moo."
*
*
* "The authors and publisher have taken care in the preparation of this book,
* but make no expressed or implied warranty of any kind and assume no
* responsibility for errors or omissions. No liability is assumed for
* incidental or consequential damages in connection with or arising out of the
* use of the information or programs contained herein."
*
* Permission is granted for this code to be used for educational purposes in
* association with the book, given proper citation if and when posted or
* reproduced.Any commercial use of this code requires the explicit written
* permission of the publisher, Addison-Wesley Professional, a division of
* Pearson Education, Inc. Send your request for permission, stating clearly
* what code you would like to use, and in what specific way, to the following
* address:
*
* Pearson Education, Inc.
* Rights and Permissions Department
* One Lake Street
* Upper Saddle River, NJ 07458
* Fax: (201) 236-3290
*/
/* This file defines the Sales_item class used in chapter 1.
* The code used in this file will be explained in
* Chapter 7 (Classes) and Chapter 14 (Overloaded Operators)
* Readers shouldn't try to understand the code in this file
* until they have read those chapters.
*/
#ifndef SALESITEM_H
// we're here only if SALESITEM_H has not yet been defined
#define SALESITEM_H
// Definition of Sales_item class and related functions goes here
#include <iostream>
#include <string>
class Sales_item {
// these declarations are explained section 7.2.1, p. 270
// and in chapter 14, pages 557, 558, 561
friend std::istream& operator>>(std::istream&, Sales_item&);
friend std::ostream& operator<<(std::ostream&, const Sales_item&);
friend bool operator<(const Sales_item&, const Sales_item&);
friend bool
operator==(const Sales_item&, const Sales_item&);
public:
// constructors are explained in section 7.1.4, pages 262 - 265
// default constructor needed to initialize members of built-in type
Sales_item(): units_sold(0), revenue(0.0) { }
Sales_item(const std::string &book):
bookNo(book), units_sold(0), revenue(0.0) { }
Sales_item(std::istream &is) { is >> *this; }
public:
// operations on Sales_item objects
// member binary operator: left-hand operand bound to implicit this pointer
Sales_item& operator+=(const Sales_item&);
// operations on Sales_item objects
std::string isbn() const { return bookNo; }
double avg_price() const;
// private members as before
private:
std::string bookNo; // implicitly initialized to the empty string
unsigned units_sold;
double revenue;
};
// used in chapter 10
inline
bool compareIsbn(const Sales_item &lhs, const Sales_item &rhs)
{ return lhs.isbn() == rhs.isbn(); }
// nonmember binary operator: must declare a parameter for each operand
Sales_item operator+(const Sales_item&, const Sales_item&);
inline bool
operator==(const Sales_item &lhs, const Sales_item &rhs)
{
// must be made a friend of Sales_item
return lhs.units_sold == rhs.units_sold &&
lhs.revenue == rhs.revenue &&
lhs.isbn() == rhs.isbn();
}
inline bool
operator!=(const Sales_item &lhs, const Sales_item &rhs)
{
return !(lhs == rhs); // != defined in terms of operator==
}
// assumes that both objects refer to the same ISBN
Sales_item& Sales_item::operator+=(const Sales_item& rhs)
{
units_sold += rhs.units_sold;
revenue += rhs.revenue;
return *this;
}
// assumes that both objects refer to the same ISBN
Sales_item
operator+(const Sales_item& lhs, const Sales_item& rhs)
{
Sales_item ret(lhs); // copy (|lhs|) into a local object that we'll return
ret += rhs; // add in the contents of (|rhs|)
return ret; // return (|ret|) by value
}
std::istream&
operator>>(std::istream& in, Sales_item& s)
{
double price;
in >> s.bookNo >> s.units_sold >> price;
// check that the inputs succeeded
if (in)
s.revenue = s.units_sold * price;
else
s = Sales_item(); // input failed: reset object to default state
return in;
}
std::ostream&
operator<<(std::ostream& out, const Sales_item& s)
{
out << s.isbn() << " " << s.units_sold << " "
<< s.revenue << " " << s.avg_price();
return out;
}
double Sales_item::avg_price() const
{
if (units_sold)
return revenue/units_sold;
else
return 0;
}
#endif#include <iostream>
using std::cin; using std::cout; using std::endl; using std::cerr;
using std::istream; using std::ostream;
#include <fstream>
using std::ifstream;
#include <string>
using std::string;
#include <vector>
using std::vector;
#include <iterator>
using std::inserter;
using std::istream_iterator; using std::ostream_iterator;
#include <algorithm>
using std::sort;
#include <numeric>
using std::accumulate;
#include "Sales_item.h"
bool compareIsbn_1(const Sales_item &sd1, const Sales_item &sd2){
return sd1.isbn() < sd2.isbn();
}
void print(ostream &os, vector<Sales_item> &vS){
ostream_iterator<Sales_item> out_iter1(os, "\n");
for (const auto &a : vS)
out_iter1 = a;
os << endl;
}
void pro_tran(istream &is, vector<Sales_item> &vS){
istream_iterator<Sales_item> item_iter(is), eof;
auto it = inserter(vS, vS.begin());
Sales_item sum = *item_iter++;
while (item_iter != eof){
if (item_iter -> isbn() == sum.isbn()){
sum += *item_iter++;
} else {
it = sum;
sum = *item_iter++;
}
}
cout << "Now the vector<Sales_item> vS has: \n";
print(cout, vS);
}
void pro_tran(istream &is, ostream &os, vector<Sales_item> &vS1){
istream_iterator<Sales_item> item_iter(is), eof;
vector<Sales_item> vS_tmp(item_iter, eof);
vS1 = vS_tmp;
cout << "Now the record has been read to vector<Sales_item> vS1 and sort : \n";
sort(vS1.begin(), vS1.end(), compareIsbn_1);
print(os, vS1);
cout << "Now using find_if_not and accumulate deal with vS1: \n";
ostream_iterator<Sales_item> out_iter(os, "\n");
//此时vS1已按isbn大小排好序，相同isbn的Sales_item对象在其中连续存储
//find_if_not返回一个迭代器，指向第一个使一元谓词为false的元素
//使用find_if_not定位isbn不同的对象位置，分区段求值
for (auto bg = vS1.begin(), ed = bg; bg != vS1.end(); bg = ed) {
ed = std::find_if_not(bg, vS1.end(),
[bg](const Sales_item &i) { return i.isbn() == bg->isbn(); });
out_iter = std::accumulate(bg, ed, Sales_item(bg -> isbn()));
}
}
int main() {
vector<Sales_item> vS, vS1;
string pt("/home/raymain/CLionProjects/CPPLv1/book_sales.txt");
ifstream input(pt), input_1(pt);
if (input.is_open() && input_1.is_open()){
pro_tran(input, vS);
pro_tran(input_1, cout, vS1);
} else {
cout << "Failed to open file" << endl;
return EXIT_FAILURE;
}
}