Why is my matrix dimensions off?

So the goal is to create a matrix and convert that to an image. Below is my code. It runs and prints out a 10x10 matrix and the image, but the checker says y has a value of [1 1] instead of [10 10]. Why is that happening?

function [N,M] = smooth_image(x)
y=x
[N,M]=size(x)
for k=2:N-1
    for c=2:M-1
        y(k,c)=mean(mean(x(k-1:k+1,c-1:c+1)))
        y
    end
end
end

[Adam]

Which y? y will be printed many times in that double for loop. Given we have no idea what the input x is it's impossible to say what we would expect y to be though for any given element.

[Brian Bowne]

I believe it is the last y, as it is defined as the "correct output matrix". Also, when I run the script every matrix y is a 10x10 matrix so I am not sure where it is getting [1 1] from.

[Adam Danz]

Please provide 'x' or provide N and M values so we don't have to think much.

[Adam]

So you are passing this to an automated marking system? I missed that detail before! y sounds like a red herring then as if you look at the output arguments, they are N and M which you simply define as the size of the input and will, indeed, each be of size [1,1]. The for loops are therefore irrelevent to the output. I assume you meant to have y as the output argument of the function.

[Brian Bowne]

That was it, I just had the wrong output. Thank you!

[Adam Danz]

That makes 3 of us who missed that!

Doh!