polished 13.31

ch13/ex13_31.cpp

@@ -1,24 +1,21 @@
 //
-//	ex13_31
-//	Exercise 13.31
-// 	Created by Soyn on 21/7/15.
-//	Add the vector<HasPtr>, and sort it.
+//  ex13_31
+//  Exercise 13.31
+//  Created by Soyn on 21/7/15.
+//  Add the vector<HasPtr>, and sort it.
 //
-#include<vector>
-#include<algorithm>
+//  Refactored by Yue Wang Jul 2015
+//
+#include <vector>
+#include <algorithm>
 #include "ex13_31.h"
 
 int main(void)
 {
-    std :: vector< HasPtr> vh;
-    std :: string s1("s"), s2("a"),s3("c");
-    HasPtr h1(s1),h2(s2),h3(s3);
-    vh.push_back(h1);
-    vh.push_back(h2);
-    vh.push_back(h3);
-    sort(vh.begin(), vh.end());
-    for( auto e : vh){
-        e.show();
-    }
+    HasPtr s{ "s" }, a{ "a" }, c{ "c" };
+    std::vector<HasPtr> vec{ s, a, c };
+    std::sort(vec.begin(), vec.end());
+
+    for (auto const& elem : vec) elem.show();
     return 0;
 }

ch13/ex13_31.h

@@ -3,42 +3,57 @@
 //  Exercise 13.31 
 //
 //  Created by pezy on 1/23/15.
-//  Copyright (c) 2015 pezy. All rights reserved.
 //
 //  Give your class a < operator and define a vector of HasPtrs. 
 //  Give that vector some elements and then sort the vector. 
 //  Note when swap is called.
 //
-//  See ex13_30.h 
+//  Refactored by Yue Wang Jul 2015
+//
 
 #ifndef CP5_ex13_11_h
 #define CP5_ex13_11_h
 
 #include <string>
 #include <iostream>
 
-class HasPtr {
+class HasPtr 
+{
 public:
     friend void swap(HasPtr&, HasPtr&);
     friend bool operator<(const HasPtr &lhs, const HasPtr &rhs);
-    HasPtr(const std::string &s = std::string()) : ps(new std::string(s)), i(0) { }
-    HasPtr(const HasPtr &hp) : ps(new std::string(*hp.ps)), i(hp.i) { }
-    HasPtr& operator=(HasPtr tmp) {
+
+    HasPtr(const std::string &s = std::string()) 
+        : ps(new std::string(s)), i(0) 
+    { }
+
+    HasPtr(const HasPtr &hp) 
+        : ps(new std::string(*hp.ps)), i(hp.i) 
+    { }
+
+    HasPtr& operator=(HasPtr tmp) 
+    {
         this->swap(tmp);
         return *this;
     }
-    ~HasPtr() {
+
+    ~HasPtr() 
+    {
         delete ps;
     }
-
-    void swap(HasPtr &rhs) {
+
+    void swap(HasPtr &rhs) 
+    {
         using std::swap;
         swap(ps, rhs.ps);
         swap(i, rhs.i);
         std::cout << "call swap(HasPtr &rhs)" << std::endl;
     }
-
-    void show() { std::cout << *ps << std::endl; }
+
+    void show() const
+    { 
+        std::cout << *ps << std::endl; 
+    }
 private:
     std::string *ps;
     int i;