Merge pull request Mooophy#159 from pezy/gcc

fixed Mooophy#158

ch12/README.md

@@ -15,7 +15,10 @@ b2 is destroyed, but the elements in b2 must not be destroyed.
 
 so b1 and b2 both have 4 elements.
 
-## [Exercise 12.2](ex12_02.h)
+## Exercise 12.2
+
+[StrBlob](ex12_02.h) | [TEST](ex12_02_TEST.cpp)
+
 ## Exercise 12.3:
 >Does this class need const versions of push_back and pop_back? If so, add them. If not, why aren’t they needed?
 

ch12/ex12_02.h

@@ -18,32 +18,43 @@ using std::vector; using std::string;
 class StrBlob {
 public:
     using size_type = vector<string>::size_type;
-    
+
     StrBlob():data(std::make_shared<vector<string>>()) { }
     StrBlob(std::initializer_list<string> il):data(std::make_shared<vector<string>>(il)) { }
-    
+
     size_type size() const { return data->size(); }
     bool empty() const { return data->empty(); }
-    
+
     void push_back(const string &t) { data->push_back(t); }
     void pop_back() {
         check(0, "pop_back on empty StrBlob");
         data->pop_back();
     }
-    const std::string& front() {
+
+    std::string& front() {
+        check(0, "front on empty StrBlob");
+        return data->front();
+    }
+
+    std::string& back() {
+        check(0, "back on empty StrBlob");
+        return data->back();
+    }
+
+    const std::string& front() const {
         check(0, "front on empty StrBlob");
         return data->front();
     }
-    const std::string& back() {
+    const std::string& back() const {
         check(0, "back on empty StrBlob");
         return data->back();
     }
-    
+
 private:
     void check(size_type i, const string &msg) const {
         if (i >= data->size()) throw std::out_of_range(msg);
     }
-    
+
 private:
     std::shared_ptr<vector<string>> data;
 };

ch12/ex12_02_TEST.cpp

@@ -0,0 +1,12 @@
+#include "ex12_02.h"
+#include <iostream>
+
+int main()
+{
+    const StrBlob csb{"hello", "world", "pezy"};
+    StrBlob sb{"hello", "world", "Mooophy"};
+
+    std::cout << csb.front() << " " << csb.back() << std::endl;
+    sb.back() = "pezy";
+    std::cout << sb.front() << " " << sb.back() << std::endl;
+}