Question

Write a method called averageVowels that takes an ArrayList of strings as a parameter and returns the average number of vowel characters (a, e, i, o, u) in all Strings in the list. If your method is passed an empty ArrayList, it should return 0.0.

Answer 1

Description:

1. Add some strings in the array list
2. pass the array list to averageVowels method
3. loop through the array list elements
4. call countVowels method to calculate vowels in the string
5. keep adding the returned number of vowels from countVowels method
6. return the average by dividing the total number of vowels by total number of strings in the list

Code copiable:

import java.util.*;
public class AverageVowels {
  
    public static int countVowels(String str)
    {
        int numVowels = 0;
        char ch;
      
        // iterate through string character by character
        for(int i = 0; i < str.length(); i++)
        {
            // get one char using index
            ch = str.charAt(i);
          
            // check if character is vowel
            if(ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u' || ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U')
            {
                //increment the count
                numVowels++;
            }
        }
      
        // return the count
        return numVowels;
    }
  
    public static int averageVowels(ArrayList arrList)
    {
        int numOfVowels = 0;
      
        // iterate throuugh Array List
        for(int i = 0; i < arrList.size(); i++)
        {
            // call method to calculate vowels in string and add
            numOfVowels += countVowels((String)arrList.get(i));
        }
      
        // return the average by dividing total number of vowels by total number of strings in array list
        return numOfVowels/arrList.size();
    }

    public static void main(String args[]) {
      // create an array list
      ArrayList arrList = new ArrayList();

      // add elements to the array list
      arrList.add("apple");
      arrList.add("fruit");
      arrList.add("Hello");
      arrList.add("aunt");
      arrList.add("uncle");
      arrList.add("pizza");
      arrList.add("byeeee");
    
      System.out.println("Average number of vowels: " + averageVowels(arrList));
   }
}

Code screenshots showing indentation:

Output: