Index in position 1 is invalid. Array indices must be positive integers or logical values problem

It gives me "Index in position 1 is invalid. Array indices must be positive integers or logical values."

How can I solve it

clc
clear all
number_of_the_yearly_day = 1:1:365; %n
T=1:1:24;
declination=23.45.*sin((2.*pi.*(number_of_the_yearly_day-80))./(365));%?
latitude=31.963158; %?
Zenith_angle=latitude-declination; %??
tilt_angle=Zenith_angle;%?
altitude=1-Zenith_angle;  %?
w=15.*(12-T);


for i=1:365
    w(i,:)=w(i-1,:)+1
end
Y=acosd(sin(altitude).*sin(latitude)-sin(declination)./(cos(altitude).*cos(latitude)));
X=asind(sin(declination).*sin(latitude)+cos(latitude).*cos(declination).*cos(w));

plot (X,Y)

Answer 1

[Asaad Abboud Alkhalaf]

i-1 = 0 and this can not be array indices it has to be 1 , 2, 3, .......