completed the assignment

first/Address.java

@@ -0,0 +1,41 @@
+package first;
+
+public class Address {
+    private double latitude;
+    private double longitude;
+    private String written_address;
+
+    public Address(double latitude, double longitude, String written_address) {
+        this.latitude = latitude;
+        this.longitude = longitude;
+        this.written_address = written_address;
+    }
+
+    public double getLatitude() {
+        return latitude;
+    }
+
+    public double getLongitude() {
+        return longitude;
+    }
+
+    public String getWrittenAddress() {
+        return written_address;
+    }
+
+    public double distanceFrom(Address otherAddress) {
+        double lat1 = (this.latitude);
+        double lon1 = (this.longitude);
+        double lat2 = (otherAddress.getLatitude());
+        double lon2 = (otherAddress.getLongitude());
+
+        double dLat = lat2 - lat1;
+        double dLon = lon2 - lon1;
+
+        double distance = Math.sqrt(Math.pow(dLat, 2) + Math.pow(dLon, 2));
+
+
+
+        return distance;
+    }
+}

first/Customer.java

@@ -0,0 +1,33 @@
+package first;
+    public class Customer {
+        private static int nextCustomerNumber = 1;
+        private int customerNumber;
+        private String name;
+        private Address address;
+
+        public Customer(String name, Address address) {
+            this.customerNumber = nextCustomerNumber++;
+            this.name = name;
+            this.address = address;
+        }
+
+        public int getCustomerNumber() {
+            return customerNumber;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public Address getAddress() {
+            return address;
+        }
+
+        public void setAddress(Address address) {
+            this.address = address;
+        }
+    }

first/Food.java

@@ -0,0 +1,27 @@
+package first;
+
+import java.util.Vector;
+
+public class Food {
+    private static Vector<Food> menu = new Vector<>();
+    private String name;
+    public int price;
+
+    public Food(String name, int price) {
+        this.name = name;
+        this.price = price;
+        menu.add(this);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getPrice() {
+        return price;
+    }
+
+    public static Vector<Food> getMenu() {
+        return menu;
+    }
+}

first/Invoice.java

@@ -0,0 +1,48 @@
+package first;
+import java.util.ArrayList;
+import java.util.List;
+public class Invoice {
+    private final Customer customer;
+    private final List<Item> items;
+    private int state;
+    private static final float TAX_RATE = 9.4f;
+    public List<Item> getItems() {
+        return items;
+    }
+    public Invoice(Customer customer) {
+        this.customer = customer;
+        this.items = new ArrayList<>();
+        this.state = -1;
+    }
+    public boolean addItem(Item item) {
+        if (state == -1) {
+            items.add(item);
+            return true;
+        }
+        return false;
+    }
+    public boolean removeItem(Item item) {
+        if (state == -1 && items.contains(item)) {
+            items.remove(item);
+            return true;
+        }
+        return false;
+    }
+    public void nextStage() {
+        state++;
+    }
+    public int getTotalPrice() {
+        int totalPrice = 0;
+        for (Item item : items) {
+            totalPrice += item.getFood().getPrice() * item.getCount();
+        }
+        float tax = totalPrice * TAX_RATE / 100;
+        return (int) Math.ceil(totalPrice + tax);
+    }
+    public Customer getCustomer() {
+        return customer;
+    }
+    public int getState() {
+        return state;
+    }
+}

first/Item.java

@@ -0,0 +1,25 @@
+package first;
+public class Item {
+    private final Food food;
+    private final int count;
+    private final String description;
+
+    public Item(Food food, int count, String description) {
+        this.food = food;
+        this.count = count;
+        if(description != null) {
+            this.description = description;
+        } else {
+            this.description = "";
+        }
+    }
+    public Food getFood() {
+        return food;
+    }
+    public int getCount() {
+        return count;
+    }
+    public String getDescription() {
+        return description;
+    }
+}

first/Restaurant.java

@@ -0,0 +1,54 @@
+package first;
+public class Restaurant {
+    public static void main(String[] args) {
+
+        Address address1 = new Address(35.7219, 51.3347, "Tehran, Iran");
+        Address address2 = new Address(35.652832, 139.839478, "Tokyo, Japan");
+
+        Customer customer1 = new Customer("Mahdi", address1);
+        Customer customer2 = new Customer("Haruto", address1);
+
+        Food food1 = new Food("Tahchin", 15);
+        Food food2 = new Food("Sushi", 25);
+
+
+        Item item1 = new Item(food1, 2, "Extra barberry");
+        Item item2 = new Item(food2, 3, "soy sauce");
+
+
+
+        Invoice invoice1 = new Invoice(customer1);
+        invoice1.addItem(item1);
+        invoice1.addItem(item2);
+
+
+        System.out.println("\n--------------------------------------\n");
+        System.out.println("Distance From Address address1 to address2 is: " + address1.distanceFrom(address2));
+        System.out.println("\n--------------------------------------\n");
+        System.out.println("First Customer's ID: " + customer1.getCustomerNumber());
+        System.out.println("Second Customer's ID: " + customer2.getCustomerNumber());
+        System.out.println("\n--------------------------------------\n");
+
+        for (int i = 0; i < Food.getMenu().size(); i++) {
+            System.out.println("Food Name: " + Food.getMenu().get(i).getName());
+        }
+
+        System.out.println("\n--------------------------------------\n");
+        if (invoice1.addItem(item1) && invoice1.addItem(item2)) System.out.println("Items added successfully");
+        else System.out.println("Items could not be added");
+
+
+        invoice1.nextStage();
+
+        System.out.println("Current state: " + invoice1.getState());
+
+        System.out.println("\n--------------------------------------\n");
+
+        for (int i = 0; i < invoice1.getItems().size(); i++) {
+            Item items = invoice1.getItems().get(i);
+            System.out.println("Food Name: " + items.getFood().getName() + " | Food Description: " + items.getDescription());
+        }
+        System.out.println("Total price: " + invoice1.getTotalPrice());
+    }
+
+}