need insight

[phoko]

I have come across:


"std::cout: or "std::cin" and others.

Why not the simple:
"cout" or "cin"?

what special function does the prefix "std" perform?

there were instances that i took out the std and the code still runs

[z05DSL3A]

Read up on namespace and scope.

[phoko]

will do that

[phoko]

from what i have read so far, it implies that when i use "using namespace std;" then i can ignore the "std" prefix.

Literally only use "std" prefix when you do not include "using namespace std" in your code.

Did i get the understanding right?

[CollinsLainzo]

@Phoko this is my understanding as well. Isn't using std::cout or std::cin all over your program unwitty, where you could just use using namespace std; once and for all?

[Peter87]

https://isocpp.org/wiki/faq/coding-standards#using-namespace-std

[z05DSL3A]

using Declarations, ie:

using std::cout;
using std::cin;
using std::endl

add names to the scope in which they are declared. The effect of this is:
» a compilation error occurs if the same name is declared elsewhere in the same scope;
» if the same name is declared in an enclosing scope, the the name in the namespace hides it.

The using directive, ie using namespace std;, does not add a name to the current scope, it only makes the names accesable from it. This means that:
» If a name is declared within a local scope it hides the name from the namespace;
» a name in a namespace hides the same name from an enclosing scope;
» a compilation error occurs if the same name is made visible from multiple namespaces or a name is made visible that hides a name in the global name space.

So, prefer Using Declarations to Using Directive but prefer full scope resolution to Using Declarations.

[phoko]

Thank you everyone, all was helpful.