System.out.println("<menu item i>");

Week 3: Objects, files and exceptions/22. Phone book 4: Menu

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+Write the method
+
+public static void start()
+
+which initialises the HashMap object needed in the phone book and prints a menu, 
+where the user can choose which operation to perform.
+
+
+The program then calls either the method 
+- addNumber,
+- findNumber or
+- listBook. 
+It is not necessary to define the methods, it is sufficient to call them. 
+All methods get a HashMap object as a parameter.
+
+
+
+An example of program execution:
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 1
+Name: Pete
+Number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 1
+Name: Jack
+Number: 54321
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Choice: 3
+Name: Jack, number: 54321
+Name: Pete, number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 2
+Name: Pete
+Number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 0
+
+
+
+
+
+
+================================================
+
+
+
+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();
+        
+        // <hide>
+        
+        String[] s = {"1","Pete","12345","1","Jack","54321", "1", "Maya", "99999", "3", "2", "Pete", "2", "Jack", "0"};
+        Scanner.setStream(s);
+        start();
+        
+        
+        
+    }
+    
+
+
+    //q22
+    public static void start() {
+        HashMap<String, String> numbers = new HashMap<>();
+        Scanner reader = new Scanner(System.in);
+        
+        while (true) {
+            // Options Menu
+            System.out.println("1. Add number");
+            System.out.println("2. Find number");
+            System.out.println("3. List numbers");
+            System.out.println("0. Exit");
+
+            // User inputs what 'option' they want
+            System.out.print("Option: ");
+            int option = Integer.parseInt(reader.nextLine());
+
+            // Exit if option is 0
+            if (option == 0) {
+                break;
+            }
+            // Add Number if option is 1
+            else if (option == 1) {
+                addNumber(numbers);
+            }
+            else if (option == 2) {
+                findNumber(numbers);
+            }
+            else if (option == 3) {
+                listBook(numbers);
+            }
+            // if none of the options exist - continue. no printouts
+            else {
+                continue;
+            }
+
+            // print 1 extra line separating subsequent option selections
+            System.out.println("");
+        }
+    }
+
+
+
+
+
+    
+}
+
+
+
+
+
+
+
+
+
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 1
+Name: Pete
+Number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 1
+Name: Jack
+Number: 54321
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 1
+Name: Maya
+Number: 99999
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 3
+Name: Jack, number: 54321
+Name: Maya, number: 99999
+Name: Pete, number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 2
+Name: Pete
+Number: 12345
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 2
+Name: Jack
+Number: 54321
+
+1. Add number
+2. Find number
+3. List numbers
+0. Exit
+Option: 0
+