What is the problem in below code??

I write a matlab code

x=[1 2 3 4 5 6 7 8];

n=length(x);

fs=100;

ts=1/fs;

tmax=(n-1)*ts;

t=0:ts:tmax;

plot(t,x)

f=-fs/2:fs/(n-1):fs/2;

z=fftshift(fft(x));

plot(f,abs(z));

and i got a error

??? Attempt to call constructor cell with incorrect letter case.

Error in ==> fftshift at 33
    idx = cell(1, numDims);

Error in ==> Untitled at 9
z=fftshift(fft(x));

How can i solve it?

Answer 1

[Walter Roberson]

You probably have created a file named Cell.m with uppercase C; that is interfering with use of cell()

Answer 2

[John D'Errico]

It runs for me, so apparently you are running different code there, probably on a different variable x, than what you have told us.

Check the variable x. What is it? LOOK AT THE CONTENTS OF x.

[Joseph George]

But i am getting that error. plz cut my program and run it in matlab. I just want to look only how the magnitude spectrum look like?? so i added just a matrix x only

[Joseph George]

What is exactly z=fftshift(fft(x)); doing??? I got problem in this step i think.