Item 1: Choose your containers with care

You know that C++ puts a variety of containers at your disposal, but do you realize just how varied that variety is? To make sure you haven’t overlooked any of your options, here’s a quick review.

• The standard STL sequence containers, vector, string, deque, and list.

• The standard STL associative containers, set, multiset, map, and multimap.

• The nonstandard sequence containers slist and rope. slist is a singly linked list, and rope is essentially a heavy-duty string. (A “rope” is a heavy-duty “string.” Get it?) You’ll find a brief overview of these nonstandard (but commonly available) containers in Item 50.

• The nonstandard associative containers hash_set, hash_multiset, hash_map, and hash_multimap. I examine these widely available hash-table-based variants on the standard associative containers in Item 25.

• vector<char> as a replacement for string. Item 13 describes the conditions under which such a replacement might make sense.

• vector as a replacement for the standard associative containers. As Item 23 makes clear, there are times when vector can outperform the standard associative containers in both time and space.

• Several standard non-STL containers, including arrays, bitset, valarray, stack, queue, and priority_queue. Because these are non-STL containers, I have little to say about them in this book, though Item 16 mentions a case where arrays are preferable to STL containers and Item 18 explains why bitset may be better than vector<bool>. It’s also worth bearing in mind that arrays can be used with STL algorithms, because pointers can be used as array iterators.