Is this undefined behaviour:
#include <string>
#include <vector>
#include <algorithm>
int main()
{
std::string s;
char buf[20];
std::copy(s.beg in(), s.end(), buf);
}
Same question again for std::vector<cha r> instead of std::string.
Do I have to go s.empty() before every time I go s.begin(), in
case begin() is undefined? 3 4435
Old Wolf wrote: Is this undefined behaviour: std::string s; char buf[20];
std::copy(s.beg in(), s.end(), buf);
No, why should it? It is an empty sequence. This applies to all
container types which can be empty as well. Of course, you cannot
dereference the the past the end iterator which is in this case
identical to 'begin()' but this is not done by 'std::copy()' or
other standard algorithms taking an input sequence.
--
<mailto:di***** ******@yahoo.co m> <http://www.dietmar-kuehl.de/>
<http://www.contendix.c om> - Software Development & Consulting
Old Wolf wrote: Is this undefined behaviour:
#include <string> #include <vector> #include <algorithm>
int main() { std::string s; char buf[20];
std::copy(s.beg in(), s.end(), buf); }
It's only undefined if s.size() is greater than 20, in which case you'd
overflow the buffer. Also note that buf will not be usable as a C-style
string after the call to std::copy(). To use it as such you'll have to
append a null character yourself.
Kristo
On 2005-03-03 00:13:23 -0500, "Old Wolf" <ol*****@inspir e.net.nz> said: Is this undefined behaviour:
#include <string> #include <vector> #include <algorithm>
int main() { std::string s; char buf[20];
std::copy(s.beg in(), s.end(), buf); }
Same question again for std::vector<cha r> instead of std::string.
Do I have to go s.empty() before every time I go s.begin(), in case begin() is undefined?
No. If the container is empty, then begin() and end() return iterators
to the same location. Which means that they are valid in the sense that
they are non-singular, they simply cannot be dereferenced.
There is nothing undefined about the code you posted (of course, it
doesn't really do anything, but that's beside the point).
--
Clark S. Cox, III cl*******@gmail .com This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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