Example: Array Element Frequency Counter in Java

// Array Element Frequency Counter
import java.util.HashMap;
import java.util.Map;

// Main class containing the entry point of the program
public class Main {
    public static void main(String[] args) {
        // Step 1: Define the input array
        int[] numbers = {10, 20, 20, 10, 30, 10, 40, 20};

        // Step 2: Create a HashMap to store element frequencies
        // Key: Array element, Value: Frequency count
        Map<Integer, Integer> frequencyMap = new HashMap<>();

        // Step 3: Iterate through the array to count frequencies
        for (int number : numbers) {
            // Check if the element is already in the map
            if (frequencyMap.containsKey(number)) {
                // If yes, increment its count
                frequencyMap.put(number, frequencyMap.get(number) + 1);
            } else {
                // If no, add it to the map with a count of 1
                frequencyMap.put(number, 1);
            }
        }

        // Step 4: Print the resulting frequency map
        System.out.println("Element Frequencies:");
        for (Map.Entry<Integer, Integer> entry : frequencyMap.entrySet()) {
            System.out.println(entry.getKey() + " : " + entry.getValue() + " times");
        }
    }
}