I have encountered <<++ and >>++ operators many time in`C++, but I don't understand what they are. What is the specific meaning and use of these operators, and how are they different from right shift and left shift operator?
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1I'm pretty sure that's just `>>` and `++` operators squished together. There's a famous question where someone wrote a dumb loop condition that resembles that. – Carcigenicate Jun 02 '18 at 17:01
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1Very related: https://stackoverflow.com/questions/1642028/what-is-the-operator-in-C even though it's different operators, and C. – Carcigenicate Jun 02 '18 at 17:02
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1Also, your title doesn't match the body. The ones in the body make sense. I don't think the ones in the title could be possible though. Sticky shift key? – Carcigenicate Jun 02 '18 at 17:04
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Can you please provide a sample code snippet involving `<<++` and `>>++`? – Ṃųỻịgǻňạcểơửṩ Jun 02 '18 at 17:07
2 Answers
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C++ compilers ignore whitespace unless in certain situations such as string literals.
<<++ and >>++ is really just a bit-shift operatior << or >>, followed by an increment operator ++.
Consider this code:
a <<++ bis equivalent toa<<++bbecause the spaces are ignored in this context, and then equivalent toa << ++b(aleft shifted by a pre-incrementedb)a << (++b)due to operator precedence. Bit shift operators have lower precedence than incrementation.
Ṃųỻịgǻňạcểơửṩ
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1That's a weird way to describe it. `a <<++ b` is equivalent to `a<<++b`, but it's not because spaces are ignored. It's more that the tokenizer parses it as `a, <<, ++, b` since it ignores whitespace (it's not that you remove the spaces, it's that the spaces are ignored), which is bound like `a << ( ++ b)` due to operator precedence. – Justin Jun 03 '18 at 05:45
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There are two separate operators in both cases: left shift (<<), right shift (>>) and increment operator (++).
You can rewrite the following:
a >>++ b
as:
a >> (++b)
joe_chip
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