I keep getting this error. I know why but i do not know how to make the program allow negative integers starting from -12 going up by 1 until 20

fid=fopen ( ' AOA vs CL . txt' , fprintf (fid, 'alp, CLIn; ' w ') ; alp0 =-2 . 2; -AR=10; e = 0.95; a 5.190457428; AOA= zeros (-12, 1, 12); CL zeros (-12, 1, 12) ; = for i =-12: 1:20 AOA (i) = i; CL(1) = a* (AOA (1) -alp0); fprint f (fid,' %8.4f %8.4f ',AOA (1),CL (1)); end plot (AOA, CL) xlabel (Alpha AOA) ylabel (Coefficient of Lift') title"Aplha vs Coefficient of Lift') axis ([-12,20,-2,2]) fclose (fid); mmand Window >HW204b Undefined function or variable 'x'. Error in HW24b (line 14) for i = 1:x (AOA) >HW204b >HW204b Subscript indices must either be real positive integers or logicals. Error in HW24b (line 14) AOA (i) i; =