Question

QUESTION:

Complete the exercise starting with the file ArrayListInt.java and Numbers.txt data file. The task is to create a class called InClass01 in file InClass01.java, with the main method that includes the code snippet in the file above, and additional methods which carry out the following tasks:

• print the list of numbers, with a count
• compute the average of the numbers
• compute the maximum and minimum of the numbers,
• filter out the even numbers (be sure to do this after the above tasks), using the method that is already in the code snippet

GIVEN ArrayListInt.java FILE

ArrayList<Integer> numbers = new ArrayList<Integer>();
Scanner input = new Scanner(new File("Numbers.txt"));
while (input.hasNextInt()) {
int n = input.nextInt();
numbers.add(n);
}

System.out.println(numbers);

//insert additional methods and calls here ...

filterEvens(numbers);
System.out.println(numbers);

// Removes all elements with even values from the given list.
public static void filterEvens(ArrayList<Integer> list) {
for (int i = list.size() - 1; i >= 0; i--) {
int n = list.get(i);
if (n % 2 == 0) {
list.remove(i);
}
}
}

GIVEN Numbers.txt FILE

98
58
48
70
66
70
98
59
36
92
95
97
54
83
90
68
36
99
96
6
52
50
22
52
15
79
82
76
27
13
48
95
37
83

Answer 1

Please do comment if you have any doubt regarding this program

Program:

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class InClass01 {
  
   public static void main(String[] args) throws FileNotFoundException {
       ArrayList<Integer> numbers = new ArrayList<Integer>();
       Scanner input = new Scanner(new File("Numbers.txt"));
       while (input.hasNextInt()) {
           int n = input.nextInt();
           numbers.add(n);
       }
       System.out.println(numbers);
      
      
       //print the list of numbers, with a count
       listOfNumbersWithCount(numbers);
      
       //   compute the average of the numbers
       averageOfNumbers(numbers);
      
       //   compute the maximum and minimum of the numbers
       minAndmaxOfNumbers(numbers);
       //   filter out the even numbers
       filterEvens(numbers);
       System.out.println(numbers);
   }
  
  
   //   print the list of numbers, with a count
   private static void listOfNumbersWithCount(ArrayList<Integer> numbers) {
       System.out.println("print the list of numbers, with a count");
       int count = 0;
       // Retrieve through the list from 0 to size of the list and increase the count from each element retrieval in the list  
       //   (OR)count of the list can also be calculated from the size of the arraylist (numbers.size())
       for(int i = 0 ; i < numbers.size() ; i++) {
           count++;
           System.out.println(numbers.get(i));
       }
       System.out.println("count of the list : " +count);
      
      
   }
  
//compute the average of the numbers
   private static void averageOfNumbers(ArrayList<Integer> numbers) {
       double sum = 0;
       for(int i = 0 ; i < numbers.size() ; i++ ) {
           sum = sum + numbers.get(i);
       }
       double average = sum / numbers.size();
       System.out.println("Average of numbers : " + average);
      
   }
   //compute the minimum and maximum of the numbers
   private static void minAndmaxOfNumbers(ArrayList<Integer> numbers) {
       System.out.println("Min of numbers " + Collections.min(numbers));
       System.out.println("Max of numbers " + Collections.max(numbers));
      
       /*or sort the array using Collections.sort(numbers) and get the first and last numbers from the list.
       Collections.sort(numbers);
       System.out.println(numbers.get(0) + " " + numbers.get(numbers.size()-1));*/
   }
   // Removes all elements with even values from the given list
   private static void filterEvens(ArrayList<Integer> list) {
       System.out.print("Filter out the even numbers from the list : ");
       for (int i = list.size() - 1; i >= 0; i--) {
           int n = list.get(i);
           if (n % 2 == 0) {
               list.remove(i);
           }
          
       }
   }

}