Strange beep when using cout

Question

today when I was working on some code of mine I came across a beeping sound when printing a buffer to the screen. Here\'s the mysterious character that produces the beep: \'

Answer 1

In ASCII the character 7 is the "bell" character that signals to the terminal that it should beep.

EDIT: To answer your followup question, it's really just for historical reasons. The old teletype terminals needed a way to alert the operator of an incoming message so a bell was used. The bell character told the terminal to ring the bell rather than print a character.

Modern terminal emulators do essentially the same thing, although they usually have an option to replace the audible bell with a visual one.