More Exceptional C++

Chapter 6. Containers, Pointers, and Containers That Aren't

Difficulty: 5

Oil and water just don't mix. Do pointers and standard containers mix any better?

1. Consider the following code:

   vector<char> v;
   // ... populate v ...
   
   char* p = &v[0];
   
   // ... do something with *p ...
   

   Is this code valid? Whether it's valid or not, how could it be improved?

2. Now consider the following code:

   template<typename T>
   void f( T& t )
   {
     typename T::value_type* p1 = &t[0];
     typename T::value_type* p2 = &*t.begin();
     // ... do something with *p1 and *p2 ...
   }
   

   Is this code valid? Discuss.

Solution

Prelude

Little Stanislaus watched his mother as she rummaged busily in the refrigerator. ...