Why do we use namespace in C++?

A namespace is a declarative region that provides a scope to the identifiers (the names of types, functions, variables, etc) inside it. Namespaces are used to organize code into logical groups and to prevent name collisions that can occur especially when your code base includes multiple libraries.

Can we use cout without namespace std?

We use it by writing using namespace std; then we can access any of the objects like cout, cin….C++

S. No.	cout	std::cout
1.	namespace std must be used in the program	Without using namespace std, you should use std::cout.
2.	cout is a predefine object of ostream class	it is used to print the data as well as values

What can I do instead of using namespace std?

The main alternatives to bringing in everything from the std namespace into the global one with using namespace std; at global scope are:

• Only bring in the actual names you need.
• Always use explicit namespace qualifications when you use a name.
• Bring in all names, but in a reduced scope (like only inside a function).

Can a program be compiled without main () function?

No you cannot unless you are writing a program in a freestanding environment (embedded environment OS kernel etc.) where the starting point need not be main() . As per the C++ standard main() is the starting point of any program in a hosted environment .

What is namespace explain with an example?

A namespace is a group of related elements that each have a unique name or identifier. A file path, which uses syntax defined by the operating system, is considered a namespace. For example, C:\Program Files\Internet Explorer is the namespace that describes where Internet Explorer files on a Windows computer.

How do you define a namespace?

In computing, a namespace is a set of signs (names) that are used to identify and refer to objects of various kinds. A namespace ensures that all of a given set of objects have unique names so that they can be easily identified.

What happens if you remove using namespace std from your code?

Almost certainly, your code uses names from the standard library without qualification, and those names are also declared in the global namespace. Thus, removing using namespace std; changes the meaning of those unqualified names, rather than just making the code fail to compile.

What is different between these two lines using namespace std using STD cout?

cout and std::cout both are same, but the only difference is that if we use cout, namespace std must be used in the program or if you are not using std namespace then you should use std::cout.

What should be the location of using namespace std in C++ code?

It is defined in the header file. So header file needs to be included. namespace is needed because if a functionalities like cout is used, but not defined in the current scope computer needs to know where to check. so namespace needs to be included.