Hash map.TXT

import java.util.HashMap;
import java.util.Map;

public class HashMapExample {
    public static void main(String[] args) {
        // Create a HashMap to store key-value pairs of String keys and Integer values
        Map<String, Integer> hashMap = new HashMap<>();

        // Adding elements to the HashMap
        hashMap.put("John", 25);
        hashMap.put("Alice", 30);
        hashMap.put("Bob", 28);

        // Accessing elements using their keys
        System.out.println("Age of John: " + hashMap.get("John"));
        System.out.println("Age of Alice: " + hashMap.get("Alice"));

        // Iterating over the HashMap using a for-each loop
        System.out.println("\nIterating over the HashMap:");
        for (Map.Entry<String, Integer> entry : hashMap.entrySet()) {
            System.out.println("Name: " + entry.getKey() + ", Age: " + entry.getValue());
        }

        // Checking if a key exists in the HashMap
        String keyToCheck = "Alice";
        if (hashMap.containsKey(keyToCheck)) {
            System.out.println("\n" + keyToCheck + " is present in the HashMap.");
        } else {
            System.out.println("\n" + keyToCheck + " is not present in the HashMap.");
        }

        // Removing an element from the HashMap
        String keyToRemove = "Bob";
        if (hashMap.containsKey(keyToRemove)) {
            hashMap.remove(keyToRemove);
            System.out.println("\n" + keyToRemove + " is removed from the HashMap.");
        } else {
            System.out.println("\n" + keyToRemove + " is not present in the HashMap.");
        }

        // Size of the HashMap
        System.out.println("\nSize of HashMap: " + hashMap.size());
    }
}