Re: Style guidance with checking bools
James Kanze <james.kanze@gmail.com> writes:
On Jun 25, 2:37 am, "Alf P. Steinbach" <al...@start.no> wrote:
* Victor Bazarov:
Alf P. Steinbach wrote:
* Angus:
[...]
If the
variable is supposed to be 'true' or 'false', then the name
is needed to reflect that the meaning is. "mybool" is
pointless. There is no difference between !a or a != false,
since 'a' is not readable.
I think you mean, "there is no difference with respect to
readability".
There is a difference with respect to readability.
You don't say "If it is hot is true then I'll go buy an ice-scream."
you say "If it is hot then I'll go buy an ice-scream."
So you should write:
if(it->isHot()){
goBuy(iceScream);
}
(Note that this also means that it isn't good design to define a
function, "doSomething" which returns true of false to indicate
success or failure, since which indicates success isn't clear.
In such cases, it's better to have an enum, with values
succeeded and failed, and test them explicitly, i.e.:
if ( doSomething() ) ... // bad
if ( doSomething() == true ) ... // worse
if ( doSomething() == succeeded ) ... // good
Even better design, reserve results for functions returning results:
try{
doSomething();
}catch(...){
// oops
}
and:
try{
result=computeSomething();
}catch(...){
// oops
}
Yes and no. The name is the thing. It's not helpful that he
chose a bad name, although the "is" is perhaps implicit.
Something like "if ( validity )" tells me nothing. With "if (
valid )", I can probably guess. And with "if ( isValid )", it's
100% clear.
And even with a name like 'x', use '!x' and not 'x == false'.
Agreed. Except that you shouldn't have a boolean named 'x'.
And notice that <iso646.h> for C and <ciso646) for C++ are standard
headers, so you can write the even more readable:
if(not isHot and isRaining){
stayAt(Home);
}
--
__Pascal Bourguignon__