Question

I’m a novice C++ programmer.
How can I find out the namespace (is this the right word in this context?) for an include like ‘iomanip’ or any other?
When using ‘std::cout’, I don’t know why it’s ‘std’ and not something else.

I hope my question is clear and worth asking.

PS: My first post here 🙂

Answer 1

How did you know that cout existed in the first place?

Because you’ve read the friendly manual, the language standard, a good book, or an online reference. The same applies to everything: Your documentation or reference will tell you the namespace in which you find your types.

Generally, everything that’s part of the C++ standard library is in the std namespace, but some things may well be in a namespace nested within. Notable examples of nested namespaces are std::placeholders and std::chrono. But you will be told the correct namespaces if you read a good reference.

Thanks to @Potatoswatter: Other constructions that use the same scope resolution syntax are static constants of classes. For example, the class std::ios_base contains a static member type seekdir with static constant values beg, cur and end; those can be accessed via std::ios_base::beg etc. Or, since the type std::ios inherits from ios_base, via std::ios::beg etc.

In many ways, a class with only static members is just a glorified namespace, and in the early days of C++ people often used nested classes to “simulate” nested namespaces, which weren’t available at the time. The scope resolution syntax is the same.