CODEWITHSUNDEEP
javaloops
Kratocus
Kratocus

Reputation: 73

Loop validation and output problems

So I have everything working except that once I enter the input required I get input like this:

1   5.0
2   6.0
3   7.0
4   8.0

I don't know what I'm doing wrong as it seems its not increasing in the right increments based on the growthRate that I input which was 50. Also can't get the organism number to increase according to the following day. Any suggestions?

//Purpose of program to predict population of organisms

import java.util.Scanner;

public class Population {
    public static void main(String[] args) {
        double growthRate = -1;
        int population = 0;
        int days = -1;
        double popResult = 0;

        Scanner keyboard = new Scanner(System.in);

        System.out.println("\nEnter the starting number of organisms:");
        population = keyboard.nextInt();

        while (population < 2) {
            System.out.println("\nError!! Please re-enter number of organisms.");
            population = keyboard.nextInt();
        }

        System.out.println("\nEnter rate of growth as percentage:");
        growthRate = keyboard.nextInt() / 100;

        while (growthRate < 0) {
            System.out.println("\nError!! Growth rate must be a positive number. Please re-enter.");
            growthRate = keyboard.nextInt();
        }

        System.out.println("\nEnter number of days organisms will grow:");
        days = keyboard.nextInt();

        while (days < 0) {
            System.out.println("\nError!! Number of days cannot be less than 1. Please re-enter.");
            days = keyboard.nextInt();
        }

        System.out.println("Days" + "\t" + "Organisms");
        System.out.println("------------------");

        popResult = population;
        growthRate = growthRate / 100;

        for (int numberOfDays = 1; numberOfDays < days; numberOfDays++) {
            System.out.println(numberOfDays + "\t" + popResult);
            popResult = (popResult * growthRate) + popResult;

        }
    }
}

Upvotes: 0

Views: 46

Answers (1)

js_248
js_248

Reputation: 2122

You are taking input for growthRate as Integer format in line

growthRate=keyboard.nextInt()/100;

If it is less than 0 then you take input without dividing by 100 as

growthRate=keyboard.nextInt();

and finally you are again dividing growthRate as growthRate=growthRate/100;

So you have to take input outside the while loop only as growthRate=keyboard.nextInt();

Modified code

import java.util.Scanner;

public class Population
{
    public static void main(String[] args)
    {
        double growthRate=-1;
        int population=0;
        int days=-1;
        double popResult=0;

        Scanner keyboard=new Scanner(System.in);

        System.out.println("\nEnter the starting number of organisms:");
        population=keyboard.nextInt();

        while(population<2)
        {
            System.out.println("\nError!! Please re-enter number of organisms.");
            population=keyboard.nextInt();
        }

        System.out.println("\nEnter rate of growth as percentage:");
        growthRate=keyboard.nextInt();

        while(growthRate<0)
        {
            System.out.println("\nError!! Growth rate must be a positive number. Please re-enter.");
            growthRate=keyboard.nextInt();
        }

        System.out.println("\nEnter number of days organisms will grow:");
        days=keyboard.nextInt();

        while(days<0)
        {
            System.out.println("\nError!! Number of days cannot be less than 1. Please re-enter.");
            days=keyboard.nextInt();
        }

        System.out.println("Days" + "\t" +  "Organisms");
        System.out.println("------------------");

        popResult=population;
        growthRate=growthRate/100;

        for(int numberOfDays=1; numberOfDays<days; numberOfDays++)
        {
            System.out.println(numberOfDays + "\t" + popResult);
            popResult=(popResult * growthRate) + popResult;

        }}}

Upvotes: 1

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