//Example 24.8
clc
disp("1''s compliment method")
disp("    1 0 0 0")
disp("    0 1 0 1   <-- 1''s complement")
disp("    -------")
disp("    1 1 0 1")
disp("No carry results and the answer is the 1''s complement of 1101 and opposite in sign, i.e. -0010.")