CODEWITHSUNDEEP
c++c++11
daparic
daparic

Reputation: 4454

What is the advantage of a pair C++ swap method?

Given,

auto a = make_pair(1,"one");
auto b = make_pair(2,"two");
a.swap(b);

When do I really need to use a.swap(b) when there is a more generalized std::swap(a,b) that works the same way.

Upvotes: 2

Views: 793

Answers (1)

Remy Lebeau
Remy Lebeau

Reputation: 596256

std::swap(a, b) is specialized for std::pair to call a.swap(b) internally. std::swap() has many container-specific specializations so it can use container-appropriate methods for the actual swapping.

If you are writing code for a specific type, consider using a.swap(b) directly (or whatever method is appropriate for that type).

If you are writing code that is generic for multiple types, use std::swap() instead, and let the compiler work out which specialization(s) to call.

Upvotes: 7

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