unable to take the value in a array

sir, the last 5th and the last 15th line give error..i have also quoted them under stars..kindly have a look at it..

if true
  % code% code
>> folder='C:\Users\Public\Videos\Sample Videos\pro\Ne';
m=0;
for k = 2 : 10
% Get the base file name.
baseFileName = sprintf('img%d.jpg', k);
% Combine it with the folder to get the full filename.
fullFileName = fullfile(folder, baseFileName);
% Read the image file into an array.
imageArray = imread(fullFileName);
a=imageArray;
figure(1);
imshow(a); 
title('color image'); 
c=rgb2gray(a); 
b=imresize(c, [512 512]); 
figure(2);
imshow(b);
title('original gray scale image');
n=512;
k=1;
for i=1:1:n
for j=1:2:n
if (j<=n-1)
s(i,k)=(b(i,j)+b(i,j+1))/2;
d(i,k)=b(i,j)-b(i,j+1);
end
k=k+1;
end
k=1;
end
for i=1:1:n 
for j=1:1:n/2
b(i,j)=s(i,j);
b(i,j+n/2)=d(i,j);
end
end
for j=1:1:n/2
for i=1:2:n
if i<=n-1
s(k,j)=(b(i,j)+b(i+1,j))/2;
d(k,j)=b(i,j)-b(i+1,j);
end
k=k+1;
end
k=1;
end
for i=1:1:n/2 
for j=1:1:n/2
b(i,j)=s(i,j);
b(i+n/2,j)=d(i,j);
end
end
figure(3);
imshow(b); 
title('image after one level of compression')
for i=1:1:n/2 
for j=1:2:n/2
if (j<=n/2-1)
s(i,k)=(b(i,j)+b(i,j+1))/2;
d(i,k)=b(i,j)-b(i,j+1);
end
k=k+1;
end
k=1;
end
for i=1:1:n/2
for j=1:1:n/4
b(i,j)=s(i,j);
b(i,j+n/4)=d(i,j);
end
end
for j=1:1:n/4
for i=1:2:n/2
if i<=n/2-1
s(k,j)=(b(i,j)+b(i+1,j))/2;
d(k,j)=b(i,j)-b(i+1,j);
end
k=k+1;
end
k=1;
end
for i=1:1:n/4
for j=1:1:n/4
b(i,j)=s(i,j);
b(i+n/4,j)=d(i,j);
end
end
figure(4);
imshow(b);
title('image after two level of compression')
for i=1:1:n/4 
for j=1:2:n/4
if (j<=n/4-1)
s(i,k)=(b(i,j)+b(i,j+1))/2;
d(i,k)=b(i,j)-b(i,j+1);
end
k=k+1;
end
k=1;
end
for i=1:1:n/4
for j=1:1:n/8
b(i,j)=s(i,j);
b(i,j+n/8)=d(i,j);
end
end
for j=1:1:n/8
for i=1:2:n/4
if i<=n/4-1
s(k,j)=(b(i,j)+b(i+1,j)/2);
d(k,j)=b(i,j)-b(i+1,j);
end
k=k+1;
end
k=1;
end
for i=1:1:n/8
for j=1:1:n/8
b (i, j)=s(i,j);
b (i+n/8, j)=d(i,j);
end
end
b=imcrop(b,[0 0 64 64]);
m=k;
*g(m)=b;*
end
figure (5);
imshow(b);
title('image after third level of compression')
b=imresize(b, [3456 4608]); 
end
for n=2:10
imshow(b);
format = 'jpg';
str = ['C:\Users\Public\Videos\Sample Videos\pro\Newr\im' num2str(k) '.jpg'] ;
*b=g(n);*
imwrite(b,str,format) ;
end
end
end

Answer 1

[dpb]

*g(m)=b;*

is the first occurrence of g so it's not been preallocated and you're trying to address a particular (nonexistant) location.

[rohan]

what could be the solution for it sir?