3.2.4 Newlines
Always use the language-specific alternative to a pure newline.
REASONING:
Some platforms use \n, some use \r\n. Hardcoding these values into your program could cause some compatibility issues with other platforms.
Use System.lineSeperator()
BAD:
System.out.println("Hello!\n");
GOOD:
System.out.println("Hello!" + System.lineSeparator());
Use std::endl or \n. std::cout will correctly format \n to the correct platform newline character. It is recommended to still use std::endl. HOWEVER, std::endl will flush the ostream, so if you want to avoid that, use a plain \n (not \r\n)