Didier Kryn <[email protected]> writes:
> Le 25/01/2016 13:23, Rainer Weikusat a écrit :
>> while (*r) if (*r++ == '/') n = r;
>
> Does it mean
>
> while (*r)
> {
> if (*r == '/')
> {
> n = r;
> r++;
> }
> }
>
> or
>
> while (*r)
> {
> if (*r == '/')
> {
> r++;
> n = r;
> }
> }
>
>
> I think the second answer is the good one. It is more readable and
> less error-prone than your example and
... doesn't work. r (for 'running pointer') needs to be incremented on
every iteration until it hits the end of the string. In case it
currently pointed to a '/', 'n' ('pointer to [start of] name') needs to
be set to the char behind the slash. As soons as *r == 0 aka !*r, n will
point to the char after the last slash in the original string, ie, to
the program name part of a program pathname.
This is even already 'optimized for simplicity' as gcc will (usually)
issue code to reload the char r points and thus, if this was supposed
'optimized', it really ought to be something like (all untested)
char const *r, *n;
int c;
n = r = arg0;
while (c = *r++) if (c == '/') n = r;
A multi-line version could look like this:
while (c = *r) {
++r;
if (c == '/') n = r;
}
Or, for people who think everything ought to be expressed as for-loop
because everything can be expressed as for-loop,
char const *r, *n;
int c0, c1;
for (n = r = arg0, c1 = 0; c0 = *r; r++) {
if (c1 == '/') n = r;
c1 = c0;
}
This is a nice progression from '[maybe unusal but] straight-forward' to
'conventional [& contorted]'.
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