What are “cerr” and “stderr”?

Question

What is the difference between them and how are they used? Can anyone point me to examples?

Specifically, how do you \"write\" to the stream in both cases and how do you

Answer 1

What is the difference between them

stderr is a FILE*, and part of the standard C library. cerr is an ostream, and part of the standard C++ library.

Also, the "screen" output is itself a stream right?

Yes, it is. But there are actually two streams that write to the screen by default: stdout/cout is for normal output and stderr/cerr is for error messages. This is useful for redirection: You can redirect stdout to a file but still have your error messages on the screen.