import java.util.*;

/**
 This is a version of the class Species, but is only a toy
 example designed to demonstrate the difference between
 parameters of a class type and parameters of a primitive type.
*/
public class DemoSpecies
{
    private String name;
    private int population;
    private double growthRate;

    /**
     Precondition: Calling object has been given values.
     Postcondition: otherObject has the same data as the
     calling object. The calling object is unchanged.
    */
    public void makeEqual(DemoSpecies otherObject)
    {
        otherObject.name = this.name;
        otherObject.population = this.population;
        otherObject.growthRate = this.growthRate;
    }

    /**
     Tries to set intVariable equal to the population of
     the calling object. But it cannot succeed, because
     arguments of a primitive type cannot be changed.
    */
    public void tryToMakeEqual(int intVariable)
    {
        intVariable = this.population;
    }

    public void readInput( )
    {
        Scanner keyboard = Scanner.create(System.in);
        System.out.println("What is the species’ name?");
        name = keyboard.nextLine( );
        System.out.println(
                      "What is the population of the species?");
        keyboard = Scanner.create(System.in);
        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 (percent 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 projectedPopulation(int years)
    {
        double populationAmount = population;
        int count = years;
        while ((count > 0) && (populationAmount > 0))
        {
            populationAmount = (populationAmount +
                         (growthRate/100) * populationAmount);
            count--;
        }
        if (populationAmount > 0)
            return (int)populationAmount;
        else
            return 0;
    }

    public void set(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(DemoSpecies otherObject)
    {
        return ((name.equalsIgnoreCase(otherObject.name))
                && (population == otherObject.population)
                && (growthRate == otherObject.growthRate));
    }
}