Should I use namespace std

Question

I just restarted C++ (I almost finished but got really busy then forgot chunks of it) and I realized that it always tells us to use namespace std, instead of putting std:: in front of things like cout or cin. My friend (who is way more advanced than me) said to start practicing using std:: rather than using namespace because it is good practice. I couldn't really understand his explanation, something about library ambiguity I think? Should I stop using namespace std?

Answer 1

using namespace std; is helpful, but there is a problem...

Let's say you are implementing your own vector.

If you use `using namespace std;`, the compiler will start complaining because there is std::vector<>.

* `using namespace` imports the whole namespace.

If you are going to use Boost, you will need to use the prefix for the standard namespace and Boost. Forgetting that could be a huge hassle.

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I, personally, prefer to use the prefix form because I know that it is cleaner.

Answer 2

For simpler programs with no clash of namespaces, using namespace std; is OK.

Answer 3

You can use it. You should understand the theory behind it and use namespaces as needed. Do not do anything just because someone sad so, ask why - that is the way to learn.