"Out of curiosity, why, if I print b, would the matrix start with 10 zeros?"
This code should never reach 'b' which would leave 'b' undefined. The i>0 condition is nested within the i<0 condition. So if i<0, than i will never be greater than 0.
Here is your code with correct formatting.
for i=-10:10
if i<0
a(i+11)=i;
if i>0
b(i+10)=i;
end
end
end
My guess is that one of your 'end' lines is misplaced.
Even if you fix it, you'd still have problems getting what you want for reasons described by madhan ravi.
