Find data in specific range

Dear all,

I'm quite new in using Matlab. I've wrote a script to determine estimation of solar declination, sd by day number, dn. I would like to know how I can find and fprintf on which dn when -0.2<= sd <= 0.2 with script below. Please help me

fout = fopen('Project_2_Matlab.res','w');

% day number, dn
dn = [1:1:365];
% Solar declination, sd
sd = 23.45*sind(360*(dn+284)/365);

for i=1:1:36
    j=i*10;
    fprintf(fout,'%3d  %3.3f \n',j, sd(j));
end

Answer 1

[Andrei Bobrov]

out = dn(sd >= -.2 & sd <= .2);

[Ahmad Rizal]

Thanks Andrei, it worked.

Answer 2

[Jose Jeremias Caballero]

Hi.

clear all
dn = 1:365;
sd = 23.45*sind(360*(dn+284)/365);
fout1  = fopen('Project_2_Matlab.res','w');
fprintf('  i dn(i) sd(i)\n');
for i=1:length(sd)
    if sd(i)>=-0.2 && sd(i)<=0.2 
    fprintf(fout1,'%3d %3d %6.3f\n',i,dn(i),sd(i));
    end
end
fclose(fout1);
type Project_2_Matlab.res
EXECUTION.

>> Untitled7
  i dn(i) sd(i)

   81  81  0.000