Is there any method for fast input of std::string in c++, instead of using std::cin?
As for fast input of numbers we can use getchar_unlocked() in our custom function.
Any help would be really appreciated.
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Maheswaran Ravisankar
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Aditya Bahuguna
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3Why isn't `std::cin` fast enough? (Well, yeah, I/O is slow. And using a different function won't change it.) – Jan 02 '14 at 20:44
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Define what you mean by "fast input of `std::string`" ... – Zac Howland Jan 02 '14 at 20:46
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Just for curiosity and adding to my knowledge a method of inputting strings faster than naive std::cin. – Aditya Bahuguna Jan 02 '14 at 20:48
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4@H2CO3: probably because `std::ios_base::sync_with_stdio(false)` and `std::cin.tie(0)` were not called. – Dietmar Kühl Jan 02 '14 at 20:48
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By Fast Input I mean a method to improve overall running time of our code where a part of problem solving is inputting a large number of strings – Aditya Bahuguna Jan 02 '14 at 20:49
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2Inputting a large number of strings from where? A human typing them in? A pipe? A file? – Yakk - Adam Nevraumont Jan 02 '14 at 20:53
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If it is coming from standard input, it won't matter how fast you make the input ... the bottleneck is the user (which you can't change). – Zac Howland Jan 02 '14 at 20:54
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Do you mean unbuffered? – Fiddling Bits Jan 02 '14 at 20:58
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1@H2CO3: Because of tons of virtual locale facet lookups perhaps? – Kerrek SB Jan 02 '14 at 21:00
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@KerrekSB So is the cost of a virtual function call comparable to that of I/O itself? – Jan 02 '14 at 21:01
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Relevant: [Fast textfile reading in c++](http://stackoverflow.com/a/17925143/85371) – sehe Jan 02 '14 at 21:05
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1@H2CO3: Not as such, but I think there may be encoding conversions that have the potential of being costly. Not sure if the default locale has some kind of optimized no-op conversion... – Kerrek SB Jan 02 '14 at 21:08