How do i have a plot automatically allocate colours to lines and label them in a legend

can anyone help me as the code below i cannot seem to get matlab to automatically allocate each new valu for r to have a different colour. it either gives all new iterations the same colour or sometimes i have it vary each interation of n with a new colour which is not what i am looking for. please help

for n=1:0.1:2
    for r=0:0.1:1
        y=(n^2)*(2*r);
        plot(n,r,'Linewidth',3.5)
        hold on
        legend({'0','0.1','0.2','0.3','0.4','0.5','0.6','0.7','0.8','0.9','1'})
        xlabel('x')
        ylabel('y')
        set(gca,'fontsize',12,'FontName', 'Times')
    end
end

Answer 1

[VBBV]

The equation y=(n^2)*(2*r); needs to be function of variables otherthan n and r

In your program n and r are used iteration counters which are in decimal increments.

MATLAB does not allow decimal increment iterations

Try this code

%   code modified 

n = 1:0.1:2;

r = 0:0.1:1;

for i=1:length(n)

for j=1:length(r)

y(i,j)=(n(i)^2)*(2*r(j));

plot(y(:,j),'Linewidth',1.5);

hold on

legend({'0','0.1','0.2','0.3','0.4','0.5','0.6','0.7','0.8','0.9','1'});

xlabel('x');

ylabel('y');

set(gca,'fontsize',12,'FontName', 'Times');

end

end