“std::endl” vs “\n”

Question

Many C++ books contain example code like this...

std::cout << \"Test line\" << std::endl;

...so I\'ve always done that too. But

Answer 1

The difference can be illustrated by the following:

std::cout << std::endl;

is equivalent to

std::cout << '\n' << std::flush;

So,

• Use std::endl If you want to force an immediate flush to the output.
• Use \n if you are worried about performance (which is probably not the case if you are using the << operator).

I use \n on most lines.
Then use std::endl at the end of a paragraph (but that is just a habit and not usually necessary).

Contrary to other claims, the \n character is mapped to the correct platform end of line sequence only if the stream is going to a file (std::cin and std::cout being special but still files (or file-like)).