Re: if(!(i%16))

bart wrote:

On 30/03/2024 22:49, fir wrote:

bart wrote:

On 30/03/2024 21:44, fir wrote:

  void bytes_dump_in_hex()
   {
     for(int i=0; i<bytes_size; i++)
     {
       if(!(i%16)) printf("\n");
>
       printf("%02x ", bytes[i]);
     }
   }
>
in the code above seem that those inner () in if(!(i%16)) are needed
>
why is that so?

>
Without them !i%16 will be parsed as (!i)%16.
>

and does it have sense?

>
It's a unary operator. Usually they are applied before binary ones. So
'++ p + n' means '(++p)+n' not '++(p+n)' which wouldn't work anyway.
>
And -2-3 means (-2)-3 or -5, not -(2-3) which would be +1.
>
However whether it makes sense is beside the point. It's how C has
always worked.
>

if ! is boolean operator and % is arithmetic then converting things to
bolean and then do arithmetoc on it seems  not much reasonable...

>
Some people think that ! should work like that, so that here:
>
    not a<b and b<c
>
the 'not' applies to the entire expression: not(a<b and b<c), rather
than (not a)<b and b<c.
>
But honestly, there are lots of things that are worse about C's set of
precedences.
>

i remember i answered then go to sleep now i dont see my answer
never thinked on this operator precedences but as i said for sure
thise "relative" (< > ==) and logical (and or not) should be last
after bitwise  (and or xor not) and arithmetic (+-*/%)
and this is as i say no matter of they do like that but the fact
thet the output of relatives and logical is boleean and boolean is not
to much use (if any) for arithmetic of bitwise - so this is for sure
relative should be before logical becouse for example
a<10 & a>-10  //say % is logical ias for me there is damn error in c and & should be logical and && eventually could be bitwise
is common usage  (so fron this 4 types mentioned logical is 4.
and relative is 3. )
as to arythmetic vs bitwice
7*9 &  78+90
im not sure
bitwise generally not fit here to much at all (to all 3 arithmetic, logical, and relative..so possiby as this is a bit outside here
it ebventually could go first to beoutside it
like
a&0xff+b&0xff00+c&0xff0000
common usage to work
so
1. bitwise
2. arithmetic
3. relative
4. logical