public static void addNumber(HashMap<String,String> numbers)

Week 3: Objects, files and exceptions/19. Phone book 1: Adding a number

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+19-22
+building a simple phonebook application one method at a time. 
+The phonebook must be able to add, search and list numbers. I
+In addition, the application has a simple menu from which you can select the desired functionality.
+
+The data structure is a hash table, where both keys and values are strings.
+
+
+===========================================
+
+19
+
+
+
+Write the method
+
+void addNumber(HashMap<String,String> numbers)
+
+which asks the user to enter a name and a number and 
+then adds them to the hash table (so that the name is the key and the number is the value).
+
+
+
+An example of a method call:
+public static void main(String[] args){
+    HashMap<String,String> numbers = new HashMap<>();
+    addNumber(numbers);
+    System.out.println(numbers);
+}
+
+
+Example execution:
+Name: Jack Java
+Number: 1234567
+{Jack Java=1234567}
+
+
+
+
+ 
+
+
+
+import java.util.Random;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Collections;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+
+
+public class Test{
+    public static void main(String[] args){
+        final Random r = new Random();
+
+            addNumber(numbers);
+            System.out.println("Book now:");
+            
+            ArrayList<String> names = new ArrayList<>(numbers.keySet());
+            Collections.sort(names);
+            for (String name : names) {
+                System.out.println(name + ": " + numbers.get(name));
+            }  
+    }
+    
+
+    // q19
+    // add name and number to input HashMap directly
+    public static void addNumber(HashMap<String,String> numbers) {
+        Scanner reader = new Scanner(System.in);
+
+        System.out.print("Name: ");
+        String name = reader.nextLine();
+        System.out.print("Number: ");
+        String number = reader.nextLine();
+        
+        numbers.put(name, number);
+    }
+
+
+}
+
+
+
+
+Testing with input [Jack, 1234-567]
+Name: Jack
+Number: 1234-567
+Book now:
+Jack: 1234-567
+
+Testing with input [Pete, 020-9876543]
+Name: Pete
+Number: 020-9876543
+Book now:
+Jack: 1234-567
+Pete: 020-9876543
+
+Testing with input [Ann, 123-456543]
+Name: Ann
+Number: 123-456543
+Book now:
+Ann: 123-456543
+Jack: 1234-567
+Pete: 020-9876543
+
+
+
+