//Species.java

import java.util.Scanner;

/**
  * Class for data on endangered species.
  * Includes a main method.
 */
public class Species
{
    private String name;
    private int population;
    private double growthRate;

    public void readInput()
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("What is the species' name?");
        name = keyboard.nextLine();

        System.out.println("What is the population of the species?");
        population = keyboard.nextInt();
        while (population < 0)
        {
            System.out.println("Population cannot be negative.");
            System.out.println("Reenter population:");
            population = keyboard.nextInt();
        }

        System.out.println("Enter growth rate (% increase per year):");
        growthRate = keyboard.nextDouble();
    }

    public void writeOutput()
    {
        System.out.println("Name = " + name);
        System.out.println("Population = " + population);
        System.out.println("Growth rate = " + growthRate + "%");
    }

    /**
     Precondition: years is a nonnegative number.
     Returns the projected population of the calling object
     after the specified number of years.
    */
    public int predictPopulation
    (
        int years
    )
    {
        int result = 0;
        double populationAmount = population;
        int count = years;
        while ((count > 0) && (populationAmount > 0))
        {
            populationAmount = (populationAmount +
                          (growthRate / 100) * populationAmount);
            count--;
        }
        if (populationAmount > 0)
            result = (int)populationAmount;

        return result;
    }

    public void setSpecies
    (
        String newName,
        int newPopulation,
        double newGrowthRate
    )
    {
        name = newName;
        if (newPopulation >= 0)
            population = newPopulation;
        else
        {
            System.out.println("ERROR: using a negative population.");
            System.exit(0);
        }
        growthRate = newGrowthRate;
    }

    public String getName()
    {
        return name;
    }

    public int getPopulation()
    {
        return population;
    }

    public double getGrowthRate()
    {
        return growthRate;
    }

    public boolean equals
    (
        Species otherObject
    )
    {
        return (name.equalsIgnoreCase(otherObject.name)) &&
               (population == otherObject.population)    &&
               (growthRate == otherObject.growthRate);
    }

    public static void main(String[] args)
    {
        Species speciesToday = new Species();
        System.out.println("Enter data on today's species:");
        speciesToday.readInput();
        speciesToday.writeOutput();
        System.out.println("Enter number of years to project:");
        Scanner keyboard = new Scanner(System.in);
        int numberOfYears = keyboard.nextInt();

        int futurePopulation = speciesToday.predictPopulation(numberOfYears);
        System.out.println("In " + numberOfYears
            + " years the population will be " + futurePopulation);
        speciesToday.setSpecies("Klingon ox", 10, 15);
        System.out.println("The new species is:");
        speciesToday.writeOutput();
    }
}