    //  The putback function is predefined in iostream. Its
    //  purpose is to replace one character at a time to the
    //  input buffer. Your code will look like this:

    	cin.putback(ch);

    //  After execution of the above line, whatever character
    //  was in ch is placed back onto the front end of the
    //  input buffer, and will be the next character to be
    //  read from it.

    //  The putback function might be used with cin to strip
    //  whitespace from the input buffer, like this:

    	cin >> ch;
    	cin.putback(ch);

    //  Recall that the cin stream extraction operator (>>)
    //  ignores tabs, spaces, and new lines, so the input buffer
    //  might look like this before the above two lines are
    //  executed:

    	|' ' ' ' ' 			//  spaces
    	|' ' 'A'			//  new line and spaces

    //  It will look like this after:

    	'A'