You can just break the loop at that point.
flags = false(1,3);
while k<=y
if flags(1)
d(i) = 0;
else
d(i)=d0+((d0^2)/2)*a-((d0^2)/2)*b*w0; % a=Deer repop rate b=rate wolves find deer
if d(i) < 0
flags(1) = true;
end
end
if flags(2)
m(i) = 0;
else
m(i)=m0+((m0^2)/2)*c-((m0^2)/2)*e*w0;% c= Moose repop rate e= rate wolves find moose
if m(i) < 0
flags(2) = true;
end
end
if flags(3)
w(i) = 0;
else
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
if w(i) < 0
flags(3) = true;
end
end
d0=d(i);
m0=m(i);
w0=w(i);
i=i+1;
k=k+1;
end
