Function for even or odd numbers

I am trying to solve the following exercice:

Write a function that fulfill the following task: Return 1 if all elements of an input vector are even and 0 else.

My answer:

function y = iseven(v)

% return the value 1 if all arguments are even, otherwise it return the value 0.

% INPUT v 1xn .. elements of the vector v.

% OUTPUT y 1x1 .. either 1 or 0.

% USAGE iseven(v)

a = rem(v,2);

b = sum(a);

if b==0;y=1;end

if b~=0;y=0;end

Unfortunantly this is not working for the vector -2 -1 0 1 2

Can someone help me to find a solution?

[Ankit]

Is this what you are looking for?

function y = iseven(v)
% return the value 1 if all arguments are even, otherwise it return the value 0.
% INPUT   v   1xn .. elements of the vector v.
% OUTPUT  y   1x1 .. either 1 or 0.
% USAGE   iseven(v)
res = mod(v,2)==0;
if all(res == 1)
    y = 1;
else
    y = 0;
end

@Stephen Thanks for pointing out

[Stephen23]

@Ankit : your function does not return any output.

[Adam]

The rem function returns a negative result when given a negative input so just summing these will not give what you want. e.g. on the input that fails for you

>> a = rem( v, 2 )
a =
     0    -1     0     1     0   

You should get used to using the debugger and command line to test these things out. Then you will easily see this for the given input and can work towards improving your solution.

Or you could just pick up a completely different ready made solution from a forum of course rather than learning to evolve your solution into a correct one...

Answer 1

[Daniel M]

function y = iseven(v)
  y = all(~mod(v,2));
end