Le 25/01/2016 16:08, Rainer Weikusat a écrit :
> Didier Kryn <kryn@???> 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;
> }
>
It might be done with a for loop. eg:
for ( ; *r ; ++r) if(*r=='/') n=r;
n++;
The for loop is the best construct for a loop with an incremental
cursor. While is rather meant for things like
while ( (c=fgets(s, sizeof(s), stdin) )
At the end of the day, there are many ways to write even simple
things :-)
Didier