Why namespace std is used...??

Answer 1

If you are reference by the line

using namespace std;

is really simple

look this example below

std::cout << "Why use std" << std::endl;

This is what you need to type to print without namespace std.

With namespace std.

this happens

cout << "Why use namepace std" << endl;

In most simple and non formal way it's like you are giving a nickname to make code more readeble.

Answer 2

Can you show code where it is used? Or explain your question more detailed please. By the way, you can lear more about namespaces.

Answer 3

So you can avoid this...
std::cout
std::cin
std::string
Lots more,you could omit it if you want..

Answer 4

easier for students to keep up with a lesson taught.
but it is considered a bad practice using it for bigger programs.
btw, 'using namespace' is just a way to shorten your code.