Create my own pre-name like "std" in C++

Question

Generally when somebody creates a console program he writes

#include <iostream>
#include <stdlib.h>

int main(){
    std::cout<<"hello world"<<std::endl;
    system("pause");
}

The std must be included to call cout and endl statements.

When I create a library using the headers and the code in the .h and .cpp, and then I include that library, I must use the name of functions/clases/structs/etc directly. How can I make it so I have to use a pre-word like the std for cout and endl?

Oh I should mention it as well: they are called **namespaces.** — , Aug 07 '13 at 22:04
@user2597243: If you are asking this kind of question (not knowing the name), I take it you should really start reading a good C++ introductory book before going any further. Please consult [this SO list](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) — Ad N, Aug 07 '13 at 22:17
I've updated your title; it's `std`, not `STD`. (C++ is case-sensitive, so it matters.) — Keith Thompson, Aug 07 '13 at 22:25

score 4 · Answer 1 · answered Aug 07 '13 at 22:04

It's called a namespace.

You can declare your own stuff inside a namespace like this:

namespace mystuff
{
    int foo();
}

To define:

int mystuff::foo()
{
    return 42;
}

To use:

int bar = mystuff::foo();

Or, import a namespace, just like you can do with std if you don't want to fully-qualify everything:

using namespace mystuff;
// ...
int bar = foo();

score 0 · Answer 2 · answered Aug 07 '13 at 22:04

0

you must define namespace like this

namespace mynamespace {
    class A{
        int func(){
        }
    }
    void func2(){}
}

you can import namespace like this

using namespace mynamespace;

answered Aug 07 '13 at 22:04

Hossein Nasr

1,346
2
17
39

score 0 · Answer 3 · answered Aug 07 '13 at 22:05

0

STD prefix is a namespace.

to define/declare a namespace you can follow that example:

namespace test
{ int f(); };

f belong to the namspace test. to call f you can

test::f();

or

using namespace test;
 ....
 f();

answered Aug 07 '13 at 22:05

alexbuisson

7,007
3
27
42

Create my own pre-name like "std" in C++

3 Answers3