C++ Primer Plus

General Properties of Algorithms

As you’ve seen again and again in this chapter, STL functions work with iterators and iterator ranges. The function prototype indicates the assumptions made about the iterators. For example, the copy() function has this prototype:

template<class InputIterator, class OutputIterator>OutputIterator copy(InputIterator first, InputIterator last,                     OutputIterator result);

Because the identifiers InputIterator and OutputIterator are template parameters, they just as easily could have been T and U. However, the STL documentation uses the template parameter names to indicate the concept that the parameter models. So this declaration tells you that the range parameters must be input iterators or better ...