/** * File: hash_map.java * Created Time: 2022-12-04 * Author: krahets (krahets@163.com) */ package chapter_hashing; import java.util.*; import utils.*; public class hash_map { public static void main(String[] args) { /* Initialize hash table */ Map map = new HashMap<>(); /* Add operation */ // Add key-value pair (key, value) to the hash table map.put(12836, "Xiao Ha"); map.put(15937, "Xiao Luo"); map.put(16750, "Xiao Suan"); map.put(13276, "Xiao Fa"); map.put(10583, "Xiao Ya"); System.out.println("\nAfter adding is complete, hash table is\nKey -> Value"); PrintUtil.printHashMap(map); /* Query operation */ // Input key into hash table to get value String name = map.get(15937); System.out.println("\nInput student ID 15937, query name " + name); /* Remove operation */ // Remove key-value pair (key, value) from hash table map.remove(10583); System.out.println("\nAfter removing 10583, hash table is\nKey -> Value"); PrintUtil.printHashMap(map); /* Traverse hash table */ System.out.println("\nTraverse key-value pairs Key->Value"); for (Map.Entry kv : map.entrySet()) { System.out.println(kv.getKey() + " -> " + kv.getValue()); } System.out.println("\nTraverse keys only Key"); for (int key : map.keySet()) { System.out.println(key); } System.out.println("\nTraverse values only Value"); for (String val : map.values()) { System.out.println(val); } } }