What do "<<" stand for?

Question

what is the purpose of them? are they used to put a command to the code?

Answer 1

In most programming languages, the << operator means bitwise rotate left.

Answer 2

In that case, the << operator is overloaded to mean redirection. You basically redirect the text to the standard output stream (cout).

Answer 3

I'm learning the basics of C++, so for example:

{
cout<<"Hello world"<<endl<<"I feel great"

do the "<<" get used as a input command? or maybe a separation mark?

Answer 4

In this case it's (the << operator) redirecting "Hello World" to a C++ object: cout. The cout object, on most OSes, is just stdout.

It can be used for input with the C++ object: cin. Now cin works with this operator: >>. Example:
int tel;
std::cin >> tel;
Of coure validating input it up to you ;) The difference is we're usually reading stdout into tel now.

Yep, stdout is basically a file. But don't worry too much about it, just look at the examples. Hope it helps.