whats wrong with this nearest neighbor zoom code

I think every thing is ok but the answer is not correct

I=imread('C:\Users\AliReza\Desktop\B.jpg');
for Channel = 1 : 3
 I1 = I(:,:,Channel);
S=2 ;
[M , N]=size(I1);
M2=S*M;
N2=S*N;
I2=zeros(M2 , N2);
for i =1:M2 
    for j = 1:N2
        x =i/S;
        y=j/S;
        x2=round(x);
        y2=round(y);
        if (x2<1)||(x2>M)||(y2<1)||(y2>N)
    I2(i , j)=0;
        else
    I2(i,j)=I1(x2 ,y2);
        end
end

   I3(:, :, Channel) = I2;
  end
  imshow(I3,[])

[John D'Errico]

What do you think is incorrect? Why do you think there is a problem? Perhaps you need to either learn to use the debugger, or you need to give more information if you seriously expect an answer.

Answer 1

[Walter Roberson]

Change

I2=zeros(M2 , N2);

to

I2 = zeros(M2 , N2, class(I));

Answer 2

[Image Analyst]

Not sure what "is not correct" means. Perhaps you'd like to see the Mathworks demo on zooming an image, attached.

Or perhaps you want to use imresize() or imcrop().

[alireza kooshafar]

dear image Analyst i write the code for gray and it works but when i want to do the same with rgb images just with adding channel i don't get the last result as i expected

[Image Analyst]

Looks like you've accepted Walter's answer so I assume you're all set now. Write back if that's not the case.