Why is std:: used by experienced coders rather than using namespace std;? [duplicate]

Question

Possible Duplicate:
Why is 'using namespace std;' considered a bad practice in C++?

The other day when I asked a question someone replied saying if someone asks a question, show them the right way to do it instead of using namespace std; which I thought was a bit weird, as using namespace std; is way easier, But I guess I'm failing right now as I am a 'beginner' coder and you guys know better.

So I guess my question is: Why std:: instead of using namespace std;?

Thanks.

Answer 1

From C++ FAQ:

Should I use using namespace std in my code?

Probably not.

People don't like typing std:: over and over, and they discover that using namespace std lets the compiler see any std name, even if unqualified. The fly in that ointment is that it lets the compiler see any std name, even the ones you didn't think about. In other words, it can create name conflicts and ambiguities.

https://isocpp.org/wiki/faq/coding-standards#using-namespace-std

Answer 2

Simply put, you are less likely to use the wrong types or functions by mistake, or name conflicts. Say you are using your own math library, plus std, and declare using both of them, in some arbitrary order. Now, they both define function pow. Which pow are you using when you invoke pow? I think it is worth the extra typing.