Setting the amount of data points before plotting

As a novice to Matlab, I am having great difficulty with the simplest of things. My current code is like this:

function Q = hydrogenusage(P)
  Q= (120*P)-(P.^2);
plot(P,Q)
xlabel('Power')
ylabel('Usage')
title('Hydrogen usage')
axis([0 120 0 4000])
grid on
end

I currently have to enter the following: hydrogenusage(0:large number) to make this work properly. But I want to edit this so I just have to enter 'hydrogenusage' and it gives me my plot. For this the amount of data points (the 0 to large number) should be specified before (therefore I tried adding the axis but that only setted the axis) in the script of the program.

Who knows what to do?

Answer 1

[Amit]

How about

function hydrogenusage
P = 0:1:4000;
Q= (120*P)-(P.^2);
plot(P,Q)
xlabel('Power')
ylabel('Usage')
title('Hydrogen usage')
axis([0 120 0 4000])
grid on
end

[N/A]

It works! Thank you so much!