Most of the time when using STL containers in C++, you want to use them with pointers to preserve run-time polymorphic behaviour. For example, a list of strings would be defined as
std::list<std::string> myStrings;
The only problem with this is that you need to remember to call delete on every element in that list before myStrings goes out of scope. That’s not a big problem you may argue, just iterate trough the whole list and delete them.
std::list<std::string *>::iterator it = myStrings.begin(); std::list<std::string *>::const_iterator end = myStrings.end(); while (it != end) delete *it++;
But when you have many containers with pointers, this duplication of code tends to become tedious. This is where templates and for_each comes into play. Add the following code to a header filer.
/// A function with the sole purpose of deleting @a ptr template<typename T> inline void deletePtr(const T& ptr) { delete ptr; } /// Calls delete on every element in @a container template<typename T> inline void deleteAllPtr(const T& container) { std::for_each(container.begin(), container.end(), deletePtr<typename T::value_type>); }
Then, when you wish to delete a container with pointers, just include the header file and call
deleteAllPtr(myStrings);
Simply beautiful 
