public static int calculateEndPopulation$($final int startPopulation,

final int maxPopulation, final double growthRate, final int periods$)$

$\{$

if $($periods $==0)$

$\{$

$//$ TODO:

return startPopulation;

$\}$

else

$\{$

$//$ TODO:

$//$ Calculate the end population for the first n$-1$ periods

$//$ The $*$start$*$ population for the n$\text{'}$th period is the $*$end$*$ population for the n$-1\text{'}$th period

int startPopulationForNthPeriod $=$ calculateEndPopulation$($startPopulation$,$ maxPopulation, growthRate, periods $-1)$;

$//$ Calculate the growth rate for the n$\text{'}$th period

double newGrowthRate $=$ startPopulationForNthPeriod $*(1+$ growthRate $*(1-($double$)$startPopulationForNthPeriod $/$ maxPopulation$))$;

$//$ Return the population for the current period

return $($int$)$ newGrowthRate;

$\}$

$\}$

I need help figuring out why the code above doesn't pass the code below:

$($Hint: make sure all calculations are done with doubles, otherwise there will be rounding errors$)$

@Test

void testCalculatePopulation$()$

$\{$

$//$ Note: Populations are whole numbers

$//$ We are using the format:

$//$ calculateEndPopulation$($startPopulation$,$ sustainablePpopulation, growthFactor,

$//$ numberOfPeriods$)$

assertEquals$(2000,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,0))$;

assertEquals$(2080,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,1))$;

assertEquals$(2162,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,2))$;

assertEquals$(2246,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,3))$;

assertEquals$(2901,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,10))$;

assertEquals$(4011,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,20))$;

assertEquals$(6448,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,40))$;

assertEquals$(8325,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,60))$;

$//$ Population slowly approaching $10000$

assertEquals$(9318,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,80))$;

assertEquals$(9738,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,100))$;

assertEquals$(9898,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,120))$;

$//$ But never quite getting to $10000$

assertEquals$(9980,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,1000))$;

assertEquals$(9980,$ Recursion.calculateEndPopulation$(2000,10000,0\mathrm{.}05,5000))$;

$\}$