function plot34(n1,n2)
fin = fopen('optics_11.dat');
fout= fopen('out.dat','w');
varNames = strsplit(fgetl(fin), ',');

varnum=length(varNames);
if n2 > varnum 
disp("ERROR:  pole andmeid")
return
end

a=readmatrix("optics_11.dat");
%n2=5
plot(a(:,n1),a(:,n2))
xlabel(varNames{n1})
ylabel(varNames{n2})
grid on

out=[a(:,n1),a(:,n2)];
t1=varNames{1};
t2=varNames{n2};
text="   "+t1+"      "+t2;
fprintf(fout,"%s\n",text);
fclose(fin);
fclose(fout);
save ("out.dat","out", "-ascii","-append")
end
