Do not use namespace using-directives.

bad_alloc.cpp

@@ -2,7 +2,8 @@
 
 #include <iostream>
 
-using namespace std;
+using std::cout;
+using std::endl;
 
 void dr_evil(int counter) {
   int *array = new int[100000000000/(1+10*counter)];

list-initializers.cpp

@@ -4,11 +4,13 @@
 #include <vector>
 #include <utility>
 
-using namespace std;
+using std::map;
+using std::pair;
+using std::vector;
 
 int main() {
     // notice how the lists are nested to match the templates' parameters:
-    map<string, vector<pair<string, int>>> name_languages_year {
+    map<std::string, vector<pair<std::string, int>>> name_languages_year {
         {"Dennis Ritchie",    {{"B",      1969}, {"C",        1973}}},
         {"Niklaus Wirth",     {{"Pascal", 1970}, {"Modula-2", 1973},
                                {"Oberon", 1986}}},
@@ -17,7 +19,7 @@ int main() {
     };
 
     // prints `Pascal':
-    cout << name_languages_year["Niklaus Wirth"].at(0).first << endl;
+    std::cout << name_languages_year["Niklaus Wirth"].at(0).first << std::endl;
 
     // adds a new entry to the map:
     name_languages_year["John McCarthy"] = {
@@ -25,5 +27,5 @@ int main() {
     };
 
     // prints 'Lisp':
-    cout << name_languages_year["John McCarthy"].at(0).first << endl;
+    std::cout << name_languages_year["John McCarthy"].at(0).first << std::endl;
 }