InventoryManagementSystem.java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

class Product {
    public Product(int id, String name, int quantity, float price) {
        this.id = id;
        this.name = name;
        this.quantity = quantity;
        this.price = price;
    }
    
    private int id;
    private String name;
    private int quantity;
    private float price;

    public int getId(){
        return id;
    }

    public void setId(int id){
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getQuantity() {
        return quantity;
    }

    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }
}

public class InventoryManagementSystem {
    static List<Product> products = new ArrayList<>();
    static Scanner scanner = new Scanner(System.in);

    private static void display(){
        String str = "\n" +
                "1. add an item\n" + //
                "2. display all the items\n" + //
                "3. search an item\n" + //
                "4. delete an item\n" + //
                "5. update an item\n" + //
                "6. calculate the inventory value\n" + //
                "7. exit the application \njust input!\n";

        System.out.println(str);
    }

    private static void addItems(){
        // id, name, quantity, price;
        System.out.print("enter id: ");
        int id = scanner.nextInt();
        scanner.nextLine();

        System.out.print("enter name: ");
        String name = scanner.nextLine();


        System.out.print("enter quantity: ");
        int quantity = scanner.nextInt();

        System.out.print("enter price: ");
        float price = scanner.nextFloat();

        Product product = new Product(id, name, quantity, price);
        products.add(product);

        System.out.print("\n producted added \n ");

    }
    
    private static void displayItems(){
        for(Product product : products){
            System.out.println("id is "+ product.getId());
            System.out.println("name is "+product.getName());
            System.out.println("quantity is "+ product.getQuantity());
            System.out.println("price is "+ product.getPrice());
            System.out.println();
        }
    }
    
    private static void search(){
        System.out.println("enter id: ");
        int targetId = scanner.nextInt();
        boolean found = false;

        for(Product product : products){
            if(product.getId() == targetId){
                System.out.println("found product");
                found = true;
            }
        }
        if(found == false){
            System.out.println("cannot find product");
        }

    }
    
    private static void updateItem(){
        System.out.println("enter id : ");
        int targetId = scanner.nextInt();
        scanner.nextLine();
        for(Product product : products){
            if(product.getId() == targetId){
                System.out.println("please enter new name");
                String name = scanner.nextLine();
                product.setName(name);

                System.out.println("please enter new quantity");
                int quantity = scanner.nextInt();
                product.setQuantity(quantity);

                System.out.println("please enter new price");
                float price = scanner.nextFloat();
                product.setPrice(price);
            }
        }
    }
    
    private static void deleteItem(){
        System.out.println("enter id : ");
        int targetId = scanner.nextInt();
        for(Product product : products){
            if(product.getId() == targetId){
                products.remove(product);
            }
        }
    }
    
    private static void calculateTotal(){
        float total = 0;
        for(Product product : products){
            // quantity * price
            total = total + product.getQuantity() * product.getPrice();
        }
        System.out.println("total value = "+total);
    }
    public static void main(String[] args) {
        
        int choice;
        do{
            display();
            choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addItems();
                    break;
                case 2:
                    displayItems();
                    break;
                case 3: 
                    search();
                    break;
                case 4:
                    deleteItem();
                    break;
                case 5:
                    updateItem();
                    break;
                case 6:
                    calculateTotal();
                    break;
                case 7: 
                    System.exit(0);
                    break;
                default: 
                    System.out.println("invalid choice");
            }
        }while (choice!=7);
    }
}