I would like to run this while loop for a inputted number of cycles. but if the input's at any point through out those cycles cause one of my equations to output to be <= 0 then I would like that equation to just output 0 for then on. I think that can be done with an if statement between each of my top 3 eaquations but I'm not sure how to do it. any help would be appreciated.

`% Predator-Prey Model Equations`

clear,clc% variables, we have to set these at the begin

d0=input('Enter Starting population of Deer: ');m0=input('Enter Starting population of Moose: '); w0=input('Enter Starting population of Wolves: '); y=input('Enter Number of years to graph: ');i=1;k=1;%fixed rates

a=.0035; % Deer repop rate

b = .0004; % Rate wolves find deer

c=.0029; % Moose repop rate

e=.00039; % rate wolves find moose

f=.15; % wolves effiecency at making food into offspring (repop rate)

g = .07; % Death rate of wolves

%h=.05; % an added death rate that could be used if you wanted to add in

%deaths from people or other animals

%equations

% D=d0+d0^2*A-B*d0^2*w0-d0^2*H;

% M=m0+m0^2*C-E*m0^2*w0-m0^2*H;

% W=w0+w0^2*F-w0^2*G;

%plot %

% here is the general idea for the plot these equations don't have the

%extra death rate like we talked about, those can be added

while k<=y d(i)=d0+((d0^2)/2)*a-((d0^2)/2)*b*w0; % a=Deer repop rate b=rate wolves find deer

m(i)=m0+((m0^2)/2)*c-((m0^2)/2)*e*w0;% c= Moose repop rate e= rate wolves find moose

w(i)=w0+((w0^2)/2)*f*(m0*b+d0*e)-g*w0; %f= wolves effiecency at making food into offspring g= death rate of wolves

d0=d(i); m0=m(i); w0=w(i); i=i+1; k=k+1;end%plotting

plot(1:i-1, d, 'o');title('Deer Over Time')grid onaxis([0, i, 0, 100000])plot(1:i-1, m, 'o')grid onaxis([0, i, 0, 100000])title('Moose over time')plot(1:i-1, w, 'o')grid onaxis([0, i, 0, 25])title('wolves over time')%display final outputs

disp('Final amount of deer')disp(d0)disp('Final amount of Moose')disp(m0)disp('Final amount of Wolves')disp(w0)

## Best Answer