The
cursor should then be placed at the beginning of line 3 on the
screen and the user should be allowed to type characters. 
Initially, the input characters should be displayed in white on the
black background.  In addition to entering regular characters
(which the program should display in the current color at the
cursor position), the program should respond to the entry of
several special characters.  The special characters should not be
echoed onto the screen.  These are the special characters and the
reactions the program must provide: