Write a program that will predict the size of a population of organisms. The pro

Question

Write a program that will predict the size of a population of organisms. The program should ask for the starting number of organisms, their average daily population increase, and the number of days they will multiply. For example, a population might begin with two organisms, have a daily average increase of 50 percent, and will be allowed to multiply for seven days. The program should use a loop to display the size of the population for each day.
Input Validation: Do not accept a number less than 2 for the starting size of the population. Do not accept a negative number for average daily population increase. Do not accept a number less than 1 for the number of days they will multiply.
You should get something like the following when you run this program:
User Prompts: (User input in bold)
Enter the starting number of organisms: 2
Enter the daily increase: .50
Enter the number of days the organisms will multiply: 7

Program Output:
Day Organisms
1 2.0
2 3.0
3 4.5
4 6.75
5 10.125
6 15.1875
7 22.78125

Modify the program you just wrote so it writes the output to a file instead of the computer screen. The number of organisms in this version of the program should be a real number rounded to two significant figures after the decimal point. Open your output text file with Notepad or another text editor to confirm the output. Write a program that will predict the size of a population of organisms. The program should ask for the starting number of organisms, their average daily population increase, and the number of days they will multiply. For example, a population might begin with two organisms, have a daily average increase of 50 percent, and will be allowed to multiply for seven days. The program should use a loop to display the size of the population for each day.
Input Validation: Do not accept a number less than 2 for the starting size of the population. Do not accept a negative number for average daily population increase. Do not accept a number less than 1 for the number of days they will multiply.
You should get something like the following when you run this program:
User Prompts: (User input in bold)
Enter the starting number of organisms: 2
Enter the daily increase: .50
Enter the number of days the organisms will multiply: 7

Program Output:
Day Organisms
1 2.0
2 3.0
3 4.5
4 6.75
5 10.125
6 15.1875
7 22.78125

Modify the program you just wrote so it writes the output to a file instead of the computer screen. The number of organisms in this version of the program should be a real number rounded to two significant figures after the decimal point. Open your output text file with Notepad or another text editor to confirm the output. Write a program that will predict the size of a population of organisms. The program should ask for the starting number of organisms, their average daily population increase, and the number of days they will multiply. For example, a population might begin with two organisms, have a daily average increase of 50 percent, and will be allowed to multiply for seven days. The program should use a loop to display the size of the population for each day.
Input Validation: Do not accept a number less than 2 for the starting size of the population. Do not accept a negative number for average daily population increase. Do not accept a number less than 1 for the number of days they will multiply.
You should get something like the following when you run this program:
User Prompts: (User input in bold)
Enter the starting number of organisms: 2
Enter the daily increase: .50
Enter the number of days the organisms will multiply: 7

Program Output:
Day Organisms
1 2.0
2 3.0
3 4.5
4 6.75
5 10.125
6 15.1875
7 22.78125

Modify the program you just wrote so it writes the output to a file instead of the computer screen. The number of organisms in this version of the program should be a real number rounded to two significant figures after the decimal point. Open your output text file with Notepad or another text editor to confirm the output.

Explanation / Answer

// First part of question

import java.util.Scanner;

public class Organism {

   public static void main(String[] args)
   {
       Scanner sc = new Scanner(System.in);
      
       System.out.print("Enter the starting number of organisms: ");
       int start = sc.nextInt();
       if (start < 2)
       {
           System.err.println("Please enter a number greater than 1");
           return;
       }
      
       System.out.print("Enter the daily increase: ");
       double increase = sc.nextDouble();
       if (increase < 0)
       {
           System.err.println("Please enter a non negative value");
           return;
       }
      
       System.out.print("Enter the number of days the organisms will multiply: ");
       int days = sc.nextInt();
       if (days < 1)
       {
           System.err.println("Please enter a number greater than 0");
           return;
       }
      
       double newSize = start;
       System.out.println("Day Organisms");
       for (int i = 0; i < days; i++)
       {
           System.out.println((i+1) +" " + newSize);
           newSize = newSize + newSize*increase;
       }
   }
}

// Second part

import java.io.FileWriter;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.Scanner;
import java.util.logging.Formatter;

public class Organism {

   public static void main(String[] args) throws IOException
   {
       Scanner sc = new Scanner(System.in);
      
       System.out.print("Enter the starting number of organisms: ");
       int start = sc.nextInt();
       if (start < 2)
       {
           System.err.println("Please enter a number greater than 1");
           return;
       }
      
       System.out.print("Enter the daily increase: ");
       double increase = sc.nextDouble();
       if (increase < 0)
       {
           System.err.println("Please enter a non negative value");
           return;
       }
      
       System.out.print("Enter the number of days the organisms will multiply: ");
       int days = sc.nextInt();
       if (days < 1)
       {
           System.err.println("Please enter a number greater than 0");
           return;
       }
      
       double newSize = start;
       DecimalFormat df = new DecimalFormat();
       df.setMaximumFractionDigits(2);
      
       FileWriter writer = new FileWriter("output.txt");
      
       writer.write("Day Organisms ");
       for (int i = 0; i < days; i++)
       {
           writer.write((i+1) +" " + df.format(newSize) + " ");
           newSize = newSize + newSize*increase;
       }
       writer.close();
   }
}

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