Everytime I run code the color of lines on my graph changes

load ENGR131_lab4_Data.mat
function h = CalcPosition(t,DC,w)
wn=1.8
o=DC.*wn;
h=1-exp(-o.*t).*cos(w.*t);
end
function x = five(t,N,V,h,w)
z=evalin('base','DC')
for N=1:2
    switch N
        case 1
            plot(t,h)
            hold on
        case 2
            plot(t,h);
            hold on
        case 3
            LineColor='k-';
            plot(t,h,':');
            hold on
        case 4
            LineColor= 'm-';
            plot(t,h,'-.');
            hold on
    end
end
end

for V=1
    subplot(2,3,V)
    t=linspace(0,20,100)
    for N=1:2
        figure(1)
        h=CalcPosition(t,DC(1,N),w(1,V))
        five(t,N,V,h,w)
        
    end
end

Answer 1

[Rik]

That makes sense, since you don't actually set the LineColor property when calling plot (instead you just have a variable with that name).

This means that every time you call this function, the same figure is being reused and a new line is plotted overlapping the existing lines, making it look as if the line colors are changing.

The solution is to do what you intended to do:

LineStyle='-.'
LineColor='m';
plot(t,h,LineStyle,'LineColor',LineColor)

You should also consider using explicit handles: create a new figure (or wipe the old one with clf) and a new axes, use hold on that axes object, plot, and release the hold.

And your use of evalin signals that you should rethink how you handle input arguments.

[Vinay]

Thanks.