finish ch17

Author: applenob

cpp_source/ch17/ex_17_4.cpp

@@ -0,0 +1,56 @@
+#include <iostream>
+#include <tuple>
+#include <string>
+#include <vector>
+#include <algorithm>
+#include <utility>
+#include <numeric>
+
+#include "ex_17_4_SalesData.h"
+
+using namespace std;
+
+// matches有三个成员：1.一个书店的索引。2.指向书店中元素的迭代器。3.指向书店中元素的迭代器。
+typedef tuple<vector<Sales_data>::size_type,
+              vector<Sales_data>::const_iterator,
+              vector<Sales_data>::const_iterator>
+    matches;
+
+// files保存每家书店的销售记录
+// findBook返回一个vector，每家销售了给定书籍的书店在其中都有一项
+vector<matches> findBook(const vector<vector<Sales_data>> &files,
+                         const string &book)
+{
+    vector<matches> ret; //初始化为空vector
+    // 对每家书店，查找给定书籍匹配的记录范围
+    for (auto it = files.cbegin; it != files.cend(); ++it)
+    {
+        // 查找具有相同ISBN的Sales_data范围，found是一个迭代器pair
+        auto found = equal_range(it->cbegin(), it->cend(), book, compareIsbn);
+        if (found.first != found.second)  // 此书店销售了给定书籍
+            // 记住此书店的索引及匹配的范围
+            ret.push_back(make_tuple(it - files.cbegin(), found.first, found.second));
+    }
+    return ret; //如果未找到匹配记录，ret为空
+}
+
+void reportResults(istream &in, ostream &os,
+                       const vector<vector<Sales_data> > &files){
+    string s;  //要查找的书
+    while (in >> s){
+        auto trans = findBook(files, s);
+        if (trans.empty()){
+            cout << s << " not found in any stores" << endl;
+            continue;  // 获得下一本要查找的书
+        }
+        for (const auto &store : trans)  // 对每家销售了给定书籍的书店
+            // get<n>返回store中tuple的指定的成员
+            os << "store " << get<0>(store) << " sales: "
+               << accumulate(get<1>(store), get<2>(store), Sales_data(s))
+               << endl;
+    }
+}
+
+int main(){
+    return 0;
+}

cpp_source/ch17/ex_17_4_SalesData.cpp

@@ -0,0 +1,106 @@
+#include <iostream>
+using std::istream; using std::ostream;
+
+#include "ex_17_4_SalesData.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;
+}

cpp_source/ch17/ex_17_4_SalesData.h

@@ -0,0 +1,87 @@
+#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

excersize/ch10.md

@@ -179,7 +179,7 @@ int main()
 }
 ```
 
-##　练习10.10
+## 练习10.10
 
 > 你认为算法不改变容器大小的原因是什么？