strlen() without include <cstring>

[howachen]

from many books said, to use strlen(), you need to include <cstringor
<string.h>, but i found the following program work, why?

#include <iostream>

using namespace std;

int main() {

char *c = "test";

cout<<strlen(c);

}
i know it is from <iostream>, so this mean the books are wrong now?

[Daniel T.]

ho******@gmail.com wrote:

from many books said, to use strlen(), you need to include <cstringor
<string.h>, but i found the following program work, why?

#include <iostream>

using namespace std;

int main() {

char *c = "test";

cout<<strlen(c);

}
i know it is from <iostream>, so this mean the books are wrong now?

In your particular implementation, iostream includes cstring, that
doesn't need to be the case though and your code might fail in some
other compiler.

--
There are two things that simply cannot be doubted, logic and perception.
Doubt those, and you no longerÊhave anyone to discuss your doubts with,
nor any ability to discuss them.

[Pete Becker]

ho******@gmail.com wrote:

>
i know it is from <iostream>, so this mean the books are wrong now?

No. It just means that with the standard library you're using, #include
<iostreamprovides a prototype for strlen.

--

-- Pete

Author of "The Standard C++ Library Extensions: a Tutorial and
Reference." For more information about this book, see
www.petebecker.com/tr1book.

[Jacek Dziedzic]

ho******@gmail.com wrote:

from many books said, to use strlen(), you need to include <cstringor
<string.h>, but i found the following program work, why?

#include <iostream>

using namespace std;

int main() {

char *c = "test";

cout<<strlen(c);

}
i know it is from <iostream>, so this mean the books are wrong now?

Consider an analogy. The books for driving licence candidates
tell you not to drive when you see a red light. Yet, sometimes
you may get lucky and manage to drive through a pedestrian
crossing at a red light and not hurt anyone.
Does that mean the books are wrong now?

HTH,
- J.