yes, none of your tests make much sense. I find your use of spaces very strange.
if C(k,1)& C(k,2) ==0
using brackets for clarity, and consistent spacing, this is equivalent to
if C(k, 1) & (C(k, 2) == 0)
which would be written more simply as
if C(k, 1) & ~C(k, 2)
hence is true when C(k, 1) is true AND C(k, 2) is false. Not what you wanted.
elseif C(k,1)& C(k,2) ==~1
~1 is 0 so this is testing exactly the same as the previous test. Why would you write ~1 in the first place, it's just a convoluted way of writing 0.
elseif C(k,1) & (C(k,2)) ==~0
Again, ~0 is just a convoluted way of writing 1. Plus we've got some brackets that don't do anything. The test is equivalent to
elseif C{k,1) & C(k, 2)
which is true when both are true. Since this is set to display 'input not same', it's clearly the wrong test.
else C(k,1) & C(k,2) ==1
is the same as the previous test.
A much simpler way to achieve the correct result with your example:
C = logical([0 0; 0 1; 1 0; 1 1]);
for row = 1:size(C, 1)
if C(row, 1) ~= C(row, 2)
disp('input not the same');
elseif C(row, 1) %guaranteed to be identical to C(row, 2)
disp('all input high');
else
disp('all input low');
end
end
And as a bonus, a vectorised version:
C = logical([0 0; 0 1; 1 0; 1 1]);
disptext = {'input not the same'; 'all input low'; 'all input high'};
disptext(1 + (C(:, 1) == C(:, 2)) + C(:, 1) .* (C(:, 1) == C(:, 2)))
edit: minor error in answer.
