If I am testing a bit (and please don't tell me better ways to test a bit - I know there are), are the inner parens redundant here?
Code:if ((work->flagbyte & 0x80) ==0) { ... }
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If I am testing a bit (and please don't tell me better ways to test a bit - I know there are), are the inner parens redundant here?
Code:if ((work->flagbyte & 0x80) ==0) { ... }
Yes, needed. The Operator man page would have told you this!
The bitwise operator has a lower precedence than the equality operator.
Ah yes, I see this now. No man pages on the system I'm using! Not all development systems are *nix.
Thank you!
A good up-to-date book on the C Programming Language would also have this information. Should be on your bookshelf!Quote:
Originally Posted by Dino
Here's a good link for you: C Operator Precedence - cppreference.com
The cppreference website is obviously targeted at C++, but they have C pages for a huge set of relevant topics. Probably the only thing they are missing is the POSIX/Windows fundamental stuff which is arguably not language-related, but which informs the language so heavily that it's hard to not have.
I recommend adding cppreference to your library of bookmarks as a useful place to go to find important language and library trivia.
My C precedence cheat sheet, designed to be very small.
All operators in a category are the same precedence, except for Binary.
In the Binary category, operators lower down are lower, as are operators to the right of a semicolon.
It seems idiotic that & is below ==, but perhaps it was meant to be occasionally used as a non-short-circuiting version of &&?Code:Postfix (LtoR) x++ x-- f() a[] o.m p->m (type){list}
Prefix (RtoL) ++x --x +x -x ! ~ *p &o (type) sizeof _Alignof
Binary (LtoR) * / % ; + -
<< >> ; < > <= >= ; == !=
& ; ^ ; | ; && ; ||
Ternary (RtoL) a ? b : c
Assign (RtoL) = += -= *= /= %= <<= >>= &= ^= |=
Comma (LtoR) ,
> It seems idiotic that & is below ==, but perhaps it was meant to be occasionally used as a non-short-circuiting version of &&?
Way way back in the mists of time....
In B and BCPL (the precursors of C), & and | were short-circuit when using in a boolean context.
And then it got messy....
Chistory
Read the section "Neonatal C"
Also Dennis Ritchie on & | vs. ==