create all the files

first/Resturant/Address.java

@@ -0,0 +1,60 @@
+public class Address {
+
+    private double latitude; // عرض جغرافیایی
+    private double longitude; // طول جغرافیایی
+    private String writtenAddress; // آدرس نوشتاری
+
+    public Address(double latitude, double longitude, String writtenAddress) {
+        this.latitude = latitude;
+        this.longitude = longitude;
+        this.writtenAddress = writtenAddress;
+    }
+
+    public double getLatitude() {
+        return latitude;
+    }
+
+    public double getLongitude() {
+        return longitude;
+    }
+
+    public String getWrittenAddress() {
+        return writtenAddress;
+    }
+
+    public void setLatitude(double latitude) {
+        this.latitude = latitude;
+    }
+
+    public void setLongitude(double longitude) {
+        this.longitude = longitude;
+    }
+
+    public void setWrittenAddress(String writtenAddress) {
+        this.writtenAddress = writtenAddress;
+    }
+
+    public double distanceFrom(Address otherAddress) {
+        double x1 = this.getLatitude();
+        double y1 = this.getLongitude();
+
+        double x2 = otherAddress.getLatitude();
+        double y2 = otherAddress.getLongitude();
+
+        double distanceX = Math.abs(x2 - x1);
+        double distanceY = Math.abs(y2 - y1);
+
+        double distance = Math.sqrt(distanceX * distanceX + distanceY * distanceY);
+
+        return Math.round(distance * 100000) / 100000.0;
+    }
+
+    @Override
+    public String toString() {
+        return "Address{" +
+                "latitude=" + latitude +
+                ", longitude=" + longitude +
+                ", writtenAddress='" + writtenAddress + "'" +
+                '}';
+    }
+}

first/Resturant/Customer.java

@@ -0,0 +1,42 @@
+
+public class Customer {
+    private static int nextId = 1;
+    private final int id;
+    private String name; // نام مشتری
+    private Address address; // آدرس مشتری
+
+    public Customer(String name, Address address) {
+        this.id = nextId++;
+        this.name = name;
+        this.address = address;
+    }
+
+    public int getCustomerNumber() {
+        return id;
+    }
+
+    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;
+    }
+
+    @Override
+    public String toString() {
+        return "Customer{" +
+                "customerId=" + id +
+                ", name='" + name +
+                "', address=" + address +
+                '}';
+    }
+}

first/Resturant/Food.java

@@ -0,0 +1,34 @@
+import java.util.Vector;
+
+public class Food {
+
+    private final static Vector<Food> menu = new Vector<>(); // لیست غذاها
+    private final String name; // نام غذا
+    private final int price; // قیمت غذا
+
+    public Food(String name, int price) {
+        this.name = name;
+        this.price = price;
+        menu.add(this);
+    }
+
+    public static Vector<Food> getMenu() {
+        return menu;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getPrice() {
+        return price;
+    }
+
+    @Override
+    public String toString() {
+        return "Food{" +
+                "name='" + name + '\'' +
+                ", price=" + price +
+                '}';
+    }
+}

first/Resturant/Invoice.java

@@ -0,0 +1,83 @@
+import java.util.ArrayList;
+import java.util.List;
+
+public class Invoice {
+
+    private static final float TAX_RATE = 0.094f; // نرخ مالیات (9.4%)
+    private int state;
+    private final Customer customer; // مشتری
+    private final List<Item> items; // لیست آیتم های فاکتور
+    private float totalPrice; // قیمت کل
+
+    public Invoice(Customer customer) {
+        this.state = -1;
+        this.customer = customer;
+        this.items = new ArrayList<>();
+        this.totalPrice = 0.0f;
+    }
+
+    public int getState() {
+        return state;
+    }
+
+    public Customer getCustomer() {
+        return customer;
+    }
+
+    public boolean addItem(Item item) {
+        if (state == -1) { // فقط در حال ثبت سفارش
+            items.add(item);
+            recalculateTotalPrice();
+            return true;
+        }
+        else {
+            return false;
+        }
+    }
+
+    public boolean removeItem(Item item) {
+        if (state == -1) { // فقط در حال ثبت سفارش
+            for (Item existingItem : items) {
+                if (existingItem.getFood().equals(item.getFood())) {
+                    items.remove(existingItem);
+                    recalculateTotalPrice();
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    public void nextStage() {
+        if (state < 3)
+            state++;
+
+    }
+
+    public List<Item> getItems() {
+        return items; // لیست آیتم های فاکتور را برمی گرداند
+    }
+
+    public int getTotalPrice() {
+        return (int)Math.ceil(totalPrice);
+    }
+
+    private void recalculateTotalPrice() {
+        totalPrice = 0.0f;
+        for (Item item : items) {
+            totalPrice += item.getCount() * item.getFood().getPrice();
+        }
+        totalPrice += totalPrice * TAX_RATE;
+
+    }
+
+    @Override
+    public String toString() {
+        return "Invoice{" +
+                "state=" + state +
+                ", customer=" + customer +
+                ", items=" + items +
+                ", totalPrice=" + totalPrice +
+                '}';
+    }
+}

first/Resturant/Item.java

@@ -0,0 +1,39 @@
+public class Item {
+
+    private final Food food;
+    private final int count;
+    private final String description;
+
+    public Item(Food food, int count) {
+        this.food = food;
+        this.count = count;
+        this.description = "_"; // Empty description
+    }
+
+    public Item(Food food, int count, String description) {
+        this.food = food;
+        this.count = count;
+        this.description = description;
+    }
+
+    public Food getFood() {
+        return food;
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public String toString() {
+        return "Item{" +
+                "food=" + food +
+                ", count=" + count +
+                ", description='" + description +
+                "'}";
+    }
+}

first/Resturant/Restaurant.java

@@ -0,0 +1,53 @@
+public class Restaurant {
+    public static void main(String[] args) {
+        Address a1 = new Address(2, 3, "Lahijan");
+        Address a2 = new Address(5, 6, "Tehran");
+
+        System.out.println("\n--------------------------------------\n");
+        System.out.println("Distance From Address a1 to a2 is: " + a1.distanceFrom(a2));
+        System.out.println("\n--------------------------------------\n");
+
+        Customer c1 = new Customer("MAMAD", a1);
+        Customer c2 = new Customer("ALI", a2);
+
+        System.out.println("First Customer's ID: " + c1.getCustomerNumber());
+        System.out.println("Second Customer's ID: " + c2.getCustomerNumber());
+
+        Food f1 = new Food("BURGER", 130);
+        Food f2 = new Food("PIZZA", 200);
+        Food f3 = new Food("PASTA", 110);
+
+        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");
+
+        Item it1 = new Item(f1, 2);
+        Item it2 = new Item(f2, 3, "MORE SAUCE");
+        Item it3 = new Item(f3, 1);
+
+        Invoice inv = new Invoice(c1);
+
+        if (inv.addItem(it1) && inv.addItem(it2)) System.out.println("Items added successfully");
+        else System.out.println("Items could not be added");
+
+        if (inv.removeItem(it3)) System.out.println("Item removed successfully");
+        else System.out.println("Failed to remove item (item doesn't exist in invoice)");
+
+        inv.nextStage();
+
+        System.out.println("Current state: " + inv.getState());
+
+        System.out.println("\n--------------------------------------\n");
+
+        for (int i = 0; i < inv.getItems().size(); i++) {
+            Item it = inv.getItems().get(i);
+            System.out.println("Food Name: " + it.getFood().getName() + " | Food Description: " + it.getDescription());
+        }
+
+        System.out.println("Total price: " + inv.getTotalPrice());
+    }
+}