A solution for exercise 17.6

ch17/ex17.4.5.6.7.8/Sales_data.cpp

@@ -0,0 +1,155 @@
+/*
+ * 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
+*/ 
+
+
+#include <iostream>
+using std::istream; using std::ostream;
+
+#include "Sales_data.h"
+Sales_data::Sales_data(std::istream &is) 
+{
+	// read will read a transaction from is into this object
+	read(is, *this);
+}
+
+double 
+Sales_data::avg_price() const {
+	if (units_sold)
+		return revenue/units_sold;
+	else
+		return 0;
+}
+
+// add the value of the given Sales_data into this object
+Sales_data& 
+Sales_data::combine(const Sales_data &rhs)
+{
+	units_sold += rhs.units_sold; // add the members of rhs into 
+	revenue += rhs.revenue;       // the members of ``this'' object
+    return *this; // return the object on which the function was called
+}
+//! = Sales_data
+Sales_data &Sales_data::operator =(const Sales_data &rhs)
+{
+    this->bookNo        = rhs.bookNo;
+    this->revenue       = rhs.revenue;
+    this->units_sold    = rhs.units_sold;
+
+    return *this;
+}
+
+//! =string
+Sales_data &Sales_data::operator =(const std::string &rhs)
+{
+    *this= Sales_data(rhs);
+    return *this;
+}
+
+//! +=
+Sales_data &Sales_data::operator +=(const Sales_data &rhs)
+{
+    this->revenue += rhs.revenue;
+    this->units_sold += rhs.units_sold;
+
+    return *this;
+}
+
+Sales_data 
+add(const Sales_data &lhs, const Sales_data &rhs)
+{
+	Sales_data sum = lhs;  // copy data members from lhs into sum
+	sum.combine(rhs);      // add data members from rhs into sum
+	return sum;
+}
+
+// transactions contain ISBN, number of copies sold, and sales price
+istream&
+read(istream &is, Sales_data &item)
+{
+	double price = 0;
+	is >> item.bookNo >> item.units_sold >> price;
+	item.revenue = price * item.units_sold;
+	return is;
+}
+
+ostream&
+print(ostream &os, const Sales_data &item)
+{
+	os << item.isbn() << " " << item.units_sold << " " 
+	   << item.revenue << " " << item.avg_price();
+	return os;
+}
+
+//! added 10.Jan 2014
+std::ostream &
+operator <<(std::ostream &os, const Sales_data &item)
+{
+    os << item.isbn() << " " << item.units_sold << " "
+       << item.revenue << " " << item.avg_price();
+
+    return os;
+}
+
+//! added 12.Jan 2014
+std::istream&
+operator >>(std::istream &is, Sales_data &s)
+{
+    double price;
+
+    //! read input
+    is >> s.bookNo >> s.units_sold >> price;
+
+    //! if successful, write into the object, give the object default state otherwise.
+    if(is)
+        s.revenue = s.units_sold * price;
+    else
+        s = Sales_data();
+
+    return is;
+}
+
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ch17/ex17.4.5.6.7.8/Sales_data.h

@@ -0,0 +1,121 @@
+/*
+ * 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
+*/ 
+
+//!
+//! Exercise 14.45:
+//! Write conversion operators to convert a Sales_data to string and to double.
+//! What values do you think these operators should return?
+//!
+#ifndef SALES_DATA_H
+#define SALES_DATA_H
+
+#include <string>
+#include <iostream>
+
+
+class Sales_data
+{
+    //! friends
+    friend Sales_data operator+(const Sales_data& lhs, const Sales_data& rhs);
+
+    friend std::ostream&
+    operator << (std::ostream& os, const Sales_data& s);
+
+    friend std::istream&
+    operator >> (std::istream& is, Sales_data& s);
+
+    friend Sales_data add(const Sales_data&, const Sales_data&);
+    friend std::ostream &print(std::ostream&, const Sales_data&);
+    friend std::istream &read(std::istream&, Sales_data&);
+
+public:
+	// constructors
+	Sales_data() = default;
+	Sales_data(const std::string &s): bookNo(s) { }
+	Sales_data(const std::string &s, unsigned n, double p):
+	           bookNo(s), units_sold(n), revenue(p*n) { }
+    Sales_data(const Sales_data &s ):
+        bookNo(s.bookNo), units_sold(s.units_sold), revenue(s.revenue)
+    {}
+
+    Sales_data(Sales_data&& s):
+        bookNo(s.bookNo), units_sold(s.units_sold), revenue(s.revenue)
+    {}
+
+    ~Sales_data(){}
+	Sales_data(std::istream &);
+
+	std::string isbn() const { return bookNo; }
+	Sales_data& combine(const Sales_data&);
+
+    //! assignments
+    Sales_data& operator  =(const Sales_data& rhs);
+    Sales_data& operator  =(const std::string&  rhs);
+    Sales_data& operator +=(const Sales_data& rhs);
+
+    //! conversion
+    explicit operator std::string () const { return bookNo; }
+    explicit operator double      () const { return revenue;}
+
+	double avg_price() const;
+private:
+	std::string bookNo;
+	unsigned units_sold = 0;
+	double revenue = 0.0;
+};
+
+
+//! overloaded operators added 10.Jan.2014 for ex14.2
+inline Sales_data
+operator+(const Sales_data& lhs, const Sales_data& rhs)
+{
+    Sales_data sum = lhs;
+    sum += rhs;
+
+    return sum;
+}
+
+std::ostream&
+operator << (std::ostream& os, const Sales_data& item);
+
+std::istream&
+operator >> (std::istream& is, Sales_data& s);
+
+// nonmember Sales_data interface functions
+Sales_data add(const Sales_data&, const Sales_data&);
+std::ostream &print(std::ostream&, const Sales_data&);
+std::istream &read(std::istream&, Sales_data&);
+
+// used in future chapters
+inline 
+bool compareIsbn(const Sales_data &lhs, const Sales_data &rhs)
+{
+	return lhs.isbn() < rhs.isbn();
+}
+#endif

ch17/ex17.4.5.6.7.8/main.cpp

@@ -35,6 +35,7 @@
 #include <vector>
 #include <algorithm>
 #include <utility>
+#include <numeric>
 
 #include "Sales_data.h"
 
@@ -53,6 +54,18 @@ typedef std::pair<std::vector<Sales_data>::size_type,
                             std::vector<Sales_data>::const_iterator>>
                                                                       matches_pair;
 
+//! for ex17.6
+//! return a struct that holds an index of a store and iterators into that store's vector
+struct matches_struct
+{
+    std::vector<Sales_data>::size_type st;
+    std::vector<Sales_data>::const_iterator first;
+    std::vector<Sales_data>::const_iterator last;
+    matches_struct(std::vector<Sales_data>::size_type s,
+                   std::vector<Sales_data>::const_iterator f,
+                   std::vector<Sales_data>::const_iterator l) : st(s), first(f), last(l) {}
+} ;
+
 //! for ex17.4
 //! return a vector with an entry for each store that sold the given book.
 std::vector<matches>
@@ -64,15 +77,20 @@ void reportResults(std::istream& in, std::ostream os,
                    const std::vector<std::vector<Sales_data>>& files);
 
 //! for ex17.5
-//! return a vector with an entry for each store that the given book
+//! return a vector with an entry for each store that sold the given book.
 std::vector<matches_pair>
 findBook_pair(const std::vector<std::vector<Sales_data> > &files,
               const std::string &book);
 
+//! for ex17.6
+//! return a vector with an entry for each store that sold the given book.
+std::vector<matches_struct>
+findBook_struct(const std::vector<std::vector<Sales_data> > &files,
+                const std::string &book);
 
 int main()
 {
-
+    return 0;
 }
 
 //! for ex17.4
@@ -118,7 +136,7 @@ void reportResults(std::istream& in, std::ostream os,
 }
 
 //! for ex17.5
-//! return a vector with an entry for each store that the given book
+//! return a vector with an entry for each store that sold the given book
 std::vector<matches_pair>
 findBook_pair(const std::vector<std::vector<Sales_data> > &files,
               const std::string &book)
@@ -133,3 +151,19 @@ findBook_pair(const std::vector<std::vector<Sales_data> > &files,
     }
     return ret;
 }
+
+//! for ex17.6
+//! return a vector with an entry for each store that sold the given book.
+std::vector<matches_struct>
+findBook_struct(const std::vector<std::vector<Sales_data> > &files,
+                const std::string &book)
+{
+    std::vector<matches_struct> ret;
+    for(auto it = files.cbegin(); it != files.cend(); ++it)
+    {
+        auto found = std::equal_range(it->cbegin(), it->cend(), book, compareIsbn);
+        if(found.first != found.second)
+            ret.push_back(matches_struct(it - files.cbegin(), found.first, found.second));
+    }
+    return ret;
+}