How to make a while loop to repeat multiple times with different values of variable?

I would like to repeat my while loop multiple times, each time with different q value (q changes from 0.5 to 4). In my example q=0. For q=0 I got one curve in a plot. How can I get the plot with multiple curves, each corresponding to different q value.

t_in_before=19;
q=0.9;
t_out=-1;
time=0;
while t_in_before>5
t_in_after=t_in_before + (q*t_out)/154 - (q*t_in_before)/154;
time=time+1;
t_in_before=t_in_after;
plot(time,t_in_after,'b.-')
hold on
end

Answer 1

[Jan]

Simply add a loop to modify q:

for q = 0.5:4
    t_in_before=19;
    t_out=-1;
    time = 0;
    while t_in_before > 5
        t_in_after=t_in_before + (q*t_out)/154 - (q*t_in_before)/154;
        time=time+1;
        t_in_before=t_in_after;
        plot(time,t_in_after,'b.-')
        hold on
    end
end

[Tomass]

Thank you! :)