For stack pop() is void, which means I need two lines of code whenever I want to get the top and pop:
auto top = s.top();
s.pop();
It would be convenient if I could just do:
auto top = s.pop();
Why is it like this?
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3For exception safety. – Jarod42 May 24 '16 at 21:51
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3@Jarod42: Do you mean to remind people that `std::stack` is *not* thread-safe? Because the two-operation API is the worst for concurrency. – Ben Voigt May 24 '16 at 21:52
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1http://cpptruths.blogspot.fr/2005/10/why-does-stdstackpop-returns-void.html – coyotte508 May 24 '16 at 21:53
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@Jarod42 If thread safety was the issue, then `top()` shouldn't return a reference. – user6378400 May 24 '16 at 21:53
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3Sometimes you want to top without popping and sometimes you want to pop without topping so I suppose its probably more efficient not to combine them. – Galik May 24 '16 at 21:53
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I think he meant exception safety. – Benjamin Lindley May 24 '16 at 21:54
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Could be due to slightly improved complexity, returning the item just popped would require a move-assignment at the least. – sjrowlinson May 24 '16 at 21:54
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1if copy constructor throws, you would lose the element in container, without recovery possible. – Jarod42 May 24 '16 at 21:55
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1@ben bought: non of the stl containers is thread safe. Reminding people about it is irrelevant. – user3104201 May 24 '16 at 21:55
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Related to [can-a-stack-have-an-exception-safe-method-for-returning-and-removing-the-top-ele](http://stackoverflow.com/questions/2620357/can-a-stack-have-an-exception-safe-method-for-returning-and-removing-the-top-ele) – Jarod42 May 24 '16 at 22:00