Re: while(T[l]<p & l<=r)

On 28.03.2024 13:18, fir wrote:

Janis Papanagnou wrote:

On 27.03.2024 12:35, fir wrote:

tell me, is while(T[l]<p & l<=r) the same as while((T[l]<p)&&(l<=r))

>
[...] If
you don't want to operate on bits but want to express a boolean
conjunction you should use '&&', though.

 
[...]
 
hovever i wopuld disagre to use "&&" instead "&" then
&& look much worse

(Well, I think that '+' looks much worse than '*', but in
math expressions I use the _appropriate_ operator anyway.)

Mind that '&' is *not* a syntactical variant of '&&'...

and probably & has no real disadvantages

it is different to '&&', it has another semantic! As said,
it's just by context-coincidence that it's equivalent _here_.

(i mean no
bigger that the intention that && should be use for boolean - which
probably comes from later c not oryginal young c

Original K&R C had '&' for bit-operations and '&&' for boolean
operations.

While, say, 'x<y & u<v' works effectively as 'x<y && u<v' (as
said, because of the evaluations to 0 and 1, general boolean
predicates, like 'p() & q()' is not the same as 'p() && q()',
even if you can use 'p()' and 'q()' in 'if'-conditions as per
the C semantics of booleans (or integers used as booleans).

You often see code like,say, 'x=length(s); y=length(t);' and
compare non-emptiness of the strings with 'if (x)' or with
'if (y)'. If you combine that condition by 'if (x & y)' you
will get wrong results, but 'if (x && y)' would be correct.

'&' is for bit-operations in scalars, '&&' is for booleans
(for logical operations, bool x bool -> bool).

 
so i probably plan to stick to &

But why stick to a bit-value operator where you want a
boolean logic operator? - You just confuse readers of your
code and unnecessarily introduce error-prone code.

(But you can of course do as you like.)

Janis