Why doesn't std::pair have iterators?

c++ stl std-pair
Frank picture Frank · Dec 6, 2012 · Viewed 7.2k times · Source

Why doesn't std::pair have iterators?

std::pair should provide iterator and const_iterator as well as begin() and end() -- just for their two members.

I think it would be useful because then we could pass them into templated functions that expect iterables, like vector or set.

Are there any downsides to this?

Answer

NPE picture NPE · Dec 6, 2012

One reason is that the two elements of a pair can be of different types. This doesn't fit with the iterator model.

The same goes for tuples, where having iterators would perhaps be even more appealing.

If you need an inexpensive homogenous container of a fixed length, you could use std::array<T, n>.

Related questions

Use of for_each on map elements

I have a map where I'd like to perform a call on every data type object member function. I yet know how to do this on any sequence but, is it possible to do it on an associative container? The …

Read More
What is the preferred/idiomatic way to insert into a map?

I have identified four different ways of inserting elements into a std::map: std::map<int, int> function; function[0] = 42; function.insert(std::map<int, int>::value_type(0, 42)); function.insert(std::pair<int, int>(0, 42)); function.…

Read More
What is the purpose of std::make_pair vs the constructor of std::pair?

What is the purpose of std::make_pair? Why not just do std::pair<int, char>(0, 'a')? Is there any difference between the two methods?

Read More