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Don’t blindly prefer emplace_back to push_back

(quuxplusone.github.io)

178 points todsacerdoti | 1 comments | 04 Mar 21 08:02 UTC | HN request time: 0.205s | source

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jokoon ◴[04 Mar 21 10:40 UTC] No.26340841[source]▶

>>26339893 (OP) #

Thanks for the article, there should be a huge list of those type of classic C++ misconceptions/FAQ style.

One of my favorite is "you don't need a linked list".

Although I'm still genuinely interested when a linked list is best suited. I'm also curious why they were invented and why they're taught, maybe just for teaching purposes...

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1. grogers ◴[04 Mar 21 11:54 UTC] No.26341290[source]▶

Use a linked list when you need to store iterators into a container while mutating it. E.g. if you are making a super naive LRU cache, you could use a map<K, list<pair<K,V>>::iterator> and a list<pair<K,V>>. This is something you can't do with vectors unless you can guarantee the capacity will never increase.

This is the most useful case of removing from the middle of a container, which linked lists are good at. Intrusive lists are common for this type of thing, instead of actually storing a list iterator.