clear
R(1)=100.0   %initial population of rabbits
F(1)=20.0    %initial population of foxs
BR_rabbit=0.5     %birth rate of rabbit 
DR_rabbit_INT=0.02   %death date of rabbit (prey) due to interaction
DR_fox=0.1     %death rate of fox
BR_fox_INT= 0.001 % birth rate of fox (predator) due to interaction

for i=1:40
 R(i+1)=R(i)+BR_rabbit*R(i)-DR_rabbit_INT*R(i)*F(i)
 F(i+1)=F(i)-DR_fox*F(i)+BR_fox_INT*F(i)*R(i)
end

figure(1); plot(R,'*')
figure(2); plot(F,'-')
