Using an if statement to differentiate between odd and even numbers

Given two Qbar matricies and the number of ply layers in a composite, I am trying to calculate the A,B, and D stress matricies.

My first error is calculating h. Given an even number of ply, h is calculated one way, and given an odd number of ply, h is calculated another way. I have tried coding that below but all my attempts have been unsuccessful.

My second problem is figuring out how to tell matlab that the odd numbered layers draw their values from one Qbar matrix and the even numbered layers draw their values from a different Qbar matrix and all the values are summed.

function[A B D] = ABD(Qbar1,Qbar2,n)

x = 0:1:n;

if n == 2*x+1 % odd number of ply

    h = -(n/2):1:(n/2);
elseif n == 2*x                 % even number of ply
    h = -n:1:n;
end 
disp(h)
for k = 1:n; i = 1:3; j = 1:3;
    for k = [1 3 5]
        Qbar(i,j,k) = Qbar1;
    end
    for k = [2 4]
        Qbar(i,j,k) = Qbar2;
    end

    A(i,j) = Qbar(i,j,k)*(h(k+1)-h(k));
    B(i,j) = (1/2)*Qbar(i,j,k)*((h(k+1)^2)-(h(k)^2));
    D(i,j) = (1/3)*Qbar(i,j,k)*((h(k+1)^3)-(h(k)^3));
end

Answer 1

[Jon Brenner]

In order to determine if a number is odd or even in MATLAB, use the mod function.

http://www.mathworks.com/help/matlab/ref/mod.html

if mod(x, 2) == 0
  % x is even
else
  % x is odd
end

[Christopher Marlar]

I'm not trying to determine if x is odd of even. I'm trying to tell matlab that if n is odd, h = something and if n is even, h is something else.

[Jon Brenner]

If you replace x with n and copy what you were trying to do into my if statement, you get this:

if mod(n, 2) == 0
  % n is even
  h = -n:1:n;
else
  % n is odd
  h = -(n/2):1:(n/2);
end