Returning even column and row in a matrix

Hi, I got a problem with some error with my home work. The requirement is created a function that can return the even column and even row.

Here is what i do

function even_index(M)

A=M(2:2:end,2:2:end)

end

how ever when i put to command window something like even_index([ 2 1 3 4; 3 2 2 1; 4 3 2 1; 7 8 5 6])

Matlab said: Error: File: even_index.m Line: 13 Column 77

Invalid experession

I saved the file into matlab already but I have the same problem with three function I created

Could someone help me explain it. Appreciate it

[Adam]

Your function only has about 5 lines as you have shown it here so I don't know how it could error on Line 13 unless the function is bigger than you show.

What does

which even_index

point to? And when you open what it points to is it the function you expect it to be?

Also, if you select the 'Pause on errors' option from the Run dropdown menu in the editor before calling your code in the command window it will stop on the line that has the error.