function echo_number
%
% Ask the user for a number, and then echo it to the screen.
%   Quit when the number given is -1.
%   
% Arguments:
%      none
%                   

  % this is the value we'll use to terminate the loop
  quit_value = -1;

  done_yet = 0;
  while (done_yet == 0)
    user_value = input('gimme a number ');
    fprintf(1, 'you typed %f \n', user_value);

    if (user_value == quit_value)
      done_yet = 1;
    end
    
  end

