Re: Variable declaration and while loops
Andre Kostur wrote:
"Victor Bazarov" <v.Abazarov@comAcast.net> wrote in news:f562h2$sdg$1
@news.datemas.de:
Zachary Turner wrote:
Hello,
This seems like an extremely basic question, and I'm a bit
embarassed that I can't answer it myself.
I just recently started using GCC and tried to type the following
code:
while ((int i = getint()) != 0)
Drop the "!= 0" part and you'll have a standard construct.
Personal style: ick. I prefer to explicitly test against 0 when
dealing with ints (I also prefer to explicitly mention NULL when
dealing with pointers too.) If the expression type is bool (or 99.9%
of the time intended to be treated as a bool, such as the void*
return of streams. It's not really intended to be used as a pointer,
but it prevents other unintentional implicit type conversion.), then
I'll do the implicit test.
Yes, as a matter of style I like seeing ints tested explicitly against
zero, but for pointers I like saying 'if (pointer) '. The syntax is
also very convenient for streams (both C and C++), where you don't care
for the variable to survive beyond the point of check.
Compare
if (FILE* blah = fopen("somename", "rb")) {
// do something with 'blah'
}
and
{
FILE* blah = fopen("somename", "rb");
if (blah != NULL) {
// do something with 'blah'
}
}
Did you notice the extra pair of braces? Ick! Besides, the former
code reads better, IMNSHO. "If file opens, do something", compared
to "open blah. if blah is not NULL ..." [..Wait a minute? Why am I
checking for NULL when the term should be "opens"? so now I need to
introduce an extra utility function or macro:
inline bool opened_OK(FILE* f) { return f != NULL; }
and write
{
FILE* blah = fopen("somename", "rb");
if (opened_OK(blah)) {
// do something with 'blah'
}
}
Ick!]
See my point?
V
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