[LAD] Mixed boolean & numbers

[Len Ovens]

On Sat, 27 Aug 2016, Will Godfrey wrote:

> I'm finding quite a lot of occasions where variables defined as 'bool' are
> sometimes being set with true or false and other times 0 or 1. On one occasion
> there is something like x = n + {boolean variable}
>
> This last one seems quite unsafe to me as I didn't think the actual value of
> true and false was guaranteed.

I do not know if the compiler takes bool = int; and forces bool = 1 if int 
= 5

According to:
http://programmers.stackexchange.com/questions/145323/when-should-you-use-bools-in-c

bool a = FALSE;
a = 5;

will give: error: no bool(const int&) available.

So, it should not be possible to set a bool to other than 0 or 1.
bool = 1;
is the same as bool = (bool) 1;
I do not know what (bool) 5 or (bool) int would do :)
bool = int; should fail to compile (assuming c++)
bool == int may should be ok
bool || int and bool && int are ok.

That is, 1 can be a bool value... 5 can not be a bool value and so should 
fail.
if(value) is different. internally I think you would find it looks like:
if(value != 0)
>
> Am I being overly cautious or should I change them all to one form or the other?

So setting a bool to 1 or 0 is ok... but leaves the next person with less 
of a clue what is happening. Changing the 1 and 0 to true and false would 
make the code easier to follow.

x = n + {boolean variable}
is a shortcut for
if({boolean variable}) {
 	x = n + 1;
} else {
 	x = n;
}

Which helps someone reading the code to understand what is going on best?
if the x = n + {boolean variable} is the next line after something that 
tells the reader {boolean value} is a bool it is ok... but what if a patch 
adds many lines in between. adding // y is a bool after might help.

So the code will work and probably not break. The code would be easier to 
read using only true or false.


--
Len Ovens
www.ovenwerks.net