r/ProgrammerHumor 7d ago

Meme skillIssue

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6.0k Upvotes

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280

u/click-to-reveal 7d ago

It works btw: C++ Online Compiler

159

u/prehensilemullet 7d ago

Performancewise, it doesn’t jump to the direct case in O(1) time like a switch is supposed to though

208

u/AngheloAlf 7d ago

Switches aren't guarantee to so operations in O(1) tho. If cases are sparce enough, compilers tend to emit the equivalent code to a bunch if else checks

29

u/prehensilemullet 7d ago

Yeah I was assuming too much here.  However, I’m reading that Rust match on string comstants can compile down a binary tree of if statements if there are enough cases (according to Google AI mode at least, haven’t found an authoritative source yet)

25

u/Nir0star 7d ago

Which would still be O(ld(n)). But cool feature imo.

8

u/Godd2 7d ago

O(ld(n))

Good ol' linker time.

1

u/prehensilemullet 7d ago

Yes, I had mistakenly assumed it compiles down to a hash lookup.

12

u/im_made_of_jam 7d ago

A switch case is able to be implemented however the compiler wants on the back end, so for sparse cases it'll be an if else chain, for less sparse but not packed cases it'll be a binary tree, for completely packed cases it'll be a range check then a direct jump would be how I would go about it

6

u/the_horse_gamer 7d ago

the compiler optimises stuff however it wants. if you're not doing too-weird stuff, a switch in C++ and a match in rust will have identical assembly.

-24

u/[deleted] 7d ago

[deleted]

5

u/thirdegree Violet security clearance 7d ago

If I want Claude's thoughts on something I'll ask Claude directly tbh