Why do we have to put std when sorting an array via begin and end iterators when that's not the case with vector,list etc?
example:
std::sort( std::begin(array), std::end(array), [](int a,int b) { return a>b;} );
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user438383
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Xavi
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it's namespace. – apple apple Jan 12 '23 at 16:36
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By "array" do you mean a `std::array` or a C-style `int[]`? – Nathan Pierson Jan 12 '23 at 16:36
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@NathanPierson on some platforms, it could be either – Caleth Jan 12 '23 at 16:39
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1Actually I guess I'm not sure what's being asked. Is it why _sort_ needs the `std` prefix? I initially read it as "why do I have to write `std::begin(array)` instead of `some_vector.begin()`?" I'd love an example of what the baseline `vector` version looks like. – Nathan Pierson Jan 12 '23 at 16:43
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1https://godbolt.org/z/vTb8ToE5K – Marek R Jan 12 '23 at 17:28
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This is due to argument dependant lookup. That vector's iterators allow you to omit std:: is not guaranteed by the standard, but it is a fairly common implementation detail.
If the result type of std::vector::begin() is a class type defined in std, then sort(vec.begin(), vec.end()) will look in std for sort as well as the global namespace, and finds std::sort (and nothing in the global namespace).
The result of std::begin(array) is a pointer, which is not a type from std, so sort(std::begin(array), std::end(array)) only looks in the global namespace, and doesn't find any functions there.
Caleth
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2@appleapple it does if `array` is a `[]` array, and doesn't if it is a `std::array` – Caleth Jan 12 '23 at 16:55
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true. I was meant to say `std::begin(vector)`, now I see you mean `array` as the raw array/std::array version – apple apple Jan 12 '23 at 18:26