- Code: Select all
package pg331num1;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
int big, little;
int years = 0;
Scanner keyboard = new Scanner(System.in);
Species newSpecies1 = new Species();
Species newSpecies2 = new Species();
Species largest = new Species();
Species smallest = new Species();
System.out.println("This program will calculate the amount of years \n" //intro
+ "for a smaller population to outnumber a larger population");
System.out.println("Lets start with the first species...");
newSpecies1.readInput(); //get input first species
System.out.println("The information you entered is ...");
newSpecies1.writeOutput(); //Display First Species
System.out.println("Now, Lets gather information on the second species...");//gt input second species
newSpecies2.readInput();
System.out.println("The information you entered is ..."); //Display second species
newSpecies2.writeOutput();
if (newSpecies1.equals(newSpecies2)){ //Check to make sure species are not equal
System.out.println("The two species are identical.");
}
else if (newSpecies1.getGrowthRate() == newSpecies2.getGrowthRate()){
System.out.println("Neither Species will ever outgrow each other.");
//System.out.println("Error 1");
return;
}
else if((newSpecies1.getPopulation() > newSpecies2.getPopulation())
&& (newSpecies1.getGrowthRate() > newSpecies2.getGrowthRate()))
{ //Checks to see which species is larger
largest = newSpecies1;
smallest = newSpecies2;
System.out.println(newSpecies2.getName() + " will never out grow " + newSpecies1.getName());
//System.out.println("Error 2");
return;
}
else if ((newSpecies2.getPopulation() > newSpecies1.getPopulation())&&
(newSpecies2.getGrowthRate() > newSpecies1.getGrowthRate()))
{
largest = newSpecies2;
smallest = newSpecies1;
System.out.println(newSpecies1.getName() + " will never out grow " + newSpecies2.getName());
//System.out.println("Error 3");
return;
}
else if((newSpecies1.getPopulation() < newSpecies2.getPopulation())
&& (newSpecies1.getGrowthRate() > newSpecies2.getGrowthRate()))
{ //Checks to see which species is larger
largest = newSpecies2;
smallest = newSpecies1;
//System.out.println("error4");
}
else if((newSpecies2.getPopulation() < newSpecies1.getPopulation())
&& (newSpecies2.getGrowthRate() > newSpecies1.getGrowthRate()))
{ //Checks to see which species is larger
largest = newSpecies1;
smallest = newSpecies2;
//System.out.println("error5");
}
else if ((newSpecies2.getPopulation() == newSpecies1.getPopulation())
&& (newSpecies1.getGrowthRate() > newSpecies2.getGrowthRate()))
{ //Checks to see which species is larger
largest = newSpecies2;
smallest = newSpecies1;
//System.out.println("error6");
}
else if ((newSpecies2.getPopulation() == newSpecies1.getPopulation())
&& (newSpecies1.getGrowthRate() < newSpecies2.getGrowthRate()))
{ //Checks to see which species is larger
largest = newSpecies1;
smallest = newSpecies2;
//System.out.println("error7");
}
big = largest.getPopulation();
little = smallest.getPopulation();
while (big >= little){
big = largest.predictPopulation(years);
little = smallest.predictPopulation(years);
//System.out.println("error8 " + years);
System.out.println(big);
System.out.println(little);
if (little > big){
System.out.println("The species " + smallest.getName() + " will outgrow "
+ largest.getName() + " in " + years + " years.");}
years++;
//System.out.println(smallest.predictPopulation(10));
}
}
}
- Code: Select all
package pg331num1;
import java.util.Scanner;
/**
Class for data on endangered species.
*/
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);
}
}
Thanks a ton guys. I hope you can help me. Is it normal for people to have so much trouble when they are first learning to program? Or am I just an idiot? It seems like I am running into a lot of "should be simple" problems.
EDIT: I figured out the endless loop. Two operators were backwards. It was bad logic on my part. Now I need to figure out why when it runs it adds an extra year to the calculation. Is that something i fix by subtracting 1? or would that make other variations untrue.
EDIT 2: I got it. Thanks guys. No more programming for me when I have stayed up so late. I found a ton of problems.... lol
