Greetings!
In looking into some C coding, I am looking for the C function that will
search for multiple occurances of a same character in a string.
For Instance:
char str[80] = "We the people of the United States";
strchr will be successful if i am looking for the "U". It returns a
successful condition.
However, if I want to parse down the string and look for each occurance
of "o", I should either get a count of 2 or the pointer moves to the
first occurance.
Is there a standard C function that returns the value(s) i am looking
for or is this something I need to write myself?
Thanks in advance for your assistance! 4 6493
David Warner wrote: Greetings!
In looking into some C coding, I am looking for the C function that will search for multiple of a same character in a string.
For Instance:
char str[80] = "We the people of the United States";
strchr will be successful if i am looking for the "U". It returns a successful condition.
However, if I want to parse down the string and look for each occurance of "o", I should either get a count of 2 or the pointer moves to the first occurance.
I understand the "count of 2" piece, but I'm not at all
sure what you mean by "or the pointer moves to the first
occurance [sic]."
Is there a standard C function that returns the value(s) i am looking for or is this something I need to write myself?
You could use strchr() in a loop, finding one target
character each time (except the last):
int count = 0;
char *where = str;
while ((where = strchr(where, 'o')) != NULL) {
++count;
++where;
}
Personally, I'd probably opt for the simpler
for (where = str; *where != '\0'; ++where) {
if (*where == 'o')
++count;
}
There's a chance the former version might be faster, especially
if `str' is very long and contains few occurrences of the target
character. However, the difference is unlikely to be significant
in the face of whatever else the program is doing (I/O, for
example), while the second is easier to read and perhaps harder
to botch.
-- Er*********@sun .com
On Mon, 25 Apr 2005, David Warner wrote: In looking into some C coding, I am looking for the C function that will search for multiple occurances of a same character in a string.
For Instance:
char str[80] = "We the people of the United States";
strchr will be successful if i am looking for the "U". It returns a successful condition.
However, if I want to parse down the string and look for each occurance of "o", I should either get a count of 2 or the pointer moves to the first occurance.
That's right. Where's the problem?
char *p;
p = strchr(str, 'e');
while (p != NULL) {
/* do something */
something(p);
/* get the next 'e' */
p = strchr(p, 'e');
}
/* now all the 'e's have been processed */
-Arthur
Arthur J. O'Dwyer wrote: On Mon, 25 Apr 2005, David Warner wrote: In looking into some C coding, I am looking for the C function that
will search for multiple occurances of a same character in a string. ... Where's the problem?
char *p; p = strchr(str, 'e'); while (p != NULL) { /* do something */ something(p); /* get the next 'e' */ p = strchr(p, 'e');
ITYM: p = strchr(p + 1, 'e');
} /* now all the 'e's have been processed */
--
Peter
"Arthur J. O'Dwyer" wrote: On Mon, 25 Apr 2005, David Warner wrote:
.... snip ... However, if I want to parse down the string and look for each occurance of "o", I should either get a count of 2 or the pointer moves to the first occurance. That's right. Where's the problem?
char *p; p = strchr(str, 'e'); while (p != NULL) { /* do something */ something(p); /* get the next 'e' */ p = strchr(p, 'e');
p = strchr(p+1, 'e'); } /* now all the 'e's have been processed */
The above change might reduce the running time when 'e' is present
:-)
--
"If you want to post a followup via groups.google.c om, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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