% flipbit.m
% flips bit i in a binary string in a vector inv
%
% inv = input vector
% i = position to change bit parity of

function r = flipbit (inv, i)
r = inv;
foo = size(r);
n = foo(2); % this is the "width" of the input vector
if i > n
    error('the specified index is larger than the size of the vector')
elseif r(i) == 0
    r(i) = 1;
elseif r(i) == 1
    r(i) = 0;
end