When must the output stream in C++ be flushed?

Question

I understand cout << \'\\n\' is preferred over cout << endl; but cout << \'\\n\' doesn\'t flush the output stream. When

Answer 1

Flushing forces an output stream to write any buffered characters. Read streamed input/output.

It depends on your application, in real-time or interactive applications you need to flush them immediately but in many cases you can wait until closing the file and leave the program to flush it automatically.