refactor 11.11 and 11.12_13

ch11/README.md

@@ -33,3 +33,7 @@ I use `set` when i just need to store the `key`, In other hand, I　would like u
 
 ## [Exercise 11.7](ex11_7.cpp)
 ## [Exercise 11.8](ex11_8.cpp)
+## [Exercise 11.9 and 11.10](ex11_9_10.cpp)
+## [Exercise 11.11](ex11_11.cpp)
+## [Exercise 11.12 and 11.13](ex11_12_13.cpp)
+## [Exercise 11.14](ex11_14.cpp)

ch11/ex11_11.cpp

@@ -1,37 +1,23 @@
-//! @Alan
-//! Exercise 11.11:
-//! Redefine bookstore without using decltype.
-//  discussion on stack overflow:
-//  http://stackoverflow.com/questions/20608365/is-it-possible-to-code-this-waywhilelambda
-//!
-#include <iostream>
-#include <map>
-#include <string>
-#include <algorithm>
-#include <list>
+//
+//  ex11_11.cpp
+//  Exercise 11.11
+//
+//  Created by pezy on 12/15/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  Redefine bookstore without using decltype.
+
+#include "../ch07/ex7_26.h"
 #include <set>
 
-
-
-class A
+bool compareIsbn(const Sales_data &lhs, const Sales_data &rhs)
 {
-    int lenth;
-public:
-    int getLenth() const {return lenth;}
-};
-
-bool compareA(const A &a1, const A &a2)
-{
-    return a1.getLenth() < a2.getLenth();
+    return lhs.isbn() < rhs.isbn();
 }
+
 int main()
 {
-    //! more approaches can be found on the post of SO.
-    bool (*fp) (const A &a1, const A &a2) = compareA;
-
-    std::multiset<A, bool (*) (const A &, const A &)> m1(fp);
-
-    return 0;
-}
-
-
+    using compareType = bool (*)(const Sales_data &lhs, const Sales_data &rhs);
+    //typedef bool(*compareType)(const Sales_data &lhs, const Sales_data &rhs);
+    std::multiset<Sales_data, compareType> bookstore(compareIsbn);
+}

ch11/ex11_12_13.cpp

@@ -1,57 +1,33 @@
-//! @Alan
-//! Exercise 11.12:
-//! Write a program to read a sequence of strings and ints, storing
-//! each into a pair. Store the pairs in a vector.
-//!
-//! Exercise 11.13:
-//! There are at least three ways to create the pairs in the program
-//! for the previous exercise. Write three versions of that program,
-//! creating the pairs in each way. Explain which form you think is
-//! easiest to write and understand, and why.
-//!
-#include <iostream>
-#include <map>
-#include <string>
-#include <algorithm>
-#include <list>
-#include <set>
+//
+//  ex11_12_13.cpp
+//  Exercise 11.12 11.13
+//
+//  Created by pezy on 12/15/14.
+//  Copyright (c) 2014 pezy. All rights reserved.
+//
+//  Write a program to read a sequence of strings and ints,
+//  storing each into a pair. Store the pairs in a vector.
+//
+//  There are at least three ways to create the pairs in the program for the previous exercise.
+//  Write three versions of that program, creating the pairs in each way.
+//  Explain which form you think is easiest to write and understand, and why.
+
+#include <vector>
 #include <utility>
-
+#include <string>
+#include <iostream>
 
 int main()
 {
+    std::vector<std::pair<std::string, int>> vec;
+    std::string str;
     int i;
-    std::string word;
-
-    std::pair<std::string, int> pair;
-    std::vector<std::pair<std::string, int>> v;
-
-    while([&]()
-    {
-          std::cout << "enter a word:\n";
-          std::cin >> word;
-          std::cout << "enter an int:\n";
-          std::cin >> i;
-
-          return word != "@q";
-}())
-    {
-        //! way 1:
-        //pair = {word, i};
-     //!^^^^^^^^^^^^^^^^^^^
-        //! way one is the easiest to write and understand.
-        //! way 2:
-        //pair = std::make_pair(word,i);
-        //! way 3:
-        pair = std::pair<std::string, int>(word,i);
-
-        v.push_back(pair);
-        for(auto e : v)
-            std::cout << e.first << " "
-                      << e.second << " ";
-        std::cout << "\n";
-    }
-    return 0;
-}
-
-
+    while (std::cin >> str >> i)
+        vec.push_back(std::pair<std::string, int>(str, i));
+        //vec.push_back(std::make_pair(str, i));
+        //vec.push_back({str, i});
+        //vec.emplace_back(str, i); //!!! easiest way.
+
+    for (const auto &p : vec)
+        std::cout << p.first << ":" << p.second << std::endl;
+}