Shop

package cart;

import java.util.*;
class Product {
    protected String name;
    protected String category;
    protected float price;

    public  Product(String name,String category, float price){
         this.name=name;
         this.category=category;
         this.price=price;
     }
    public Product() {};

}

class Cart {

    //creating collection of Object from the class Product
    static Collection<Product>collection=new ArrayList<Product>();


    //adding Objects to the collection
    public static  void addProduct(Product product) {
        collection.add(product);
    }

    //printing Objects if they are from the given category
    public static void printByCategory(String category) {
        for(Product p:collection) {
            if(p.category==category) {
                System.out.println(p.name);
                }
            }
    }

    //finding the total sum of the products
    public static float getTotalPrice() {
        float total=0f;
        for(Product p:collection)
            total+=p.price;
         return total;
    }

    //printing the Receipt
    public static void printPaymentReceipt() {
       float total=0f;
       List<Product> list=new ArrayList<>(collection);
       int n=list.size();
       for(int i=0;i<n;i++) {
           int quantity=1;
           for(int j=i+1;j<n;j++) {
               if(list.get(i).name.equals(list.get(j).name)) {
                   if(list.get(i).price==list.get(j).price) {
                       quantity++;
                       list.remove(j);
                       n--;
                    }
                 }
              }
           System.out.println(list.get(i).name+" "+quantity+" "+list.get(i).price+" "+list.get(i).price*quantity+" ");
           total+=list.get(i).price*quantity;
           }

       System.out.printf("Total is: %.2f",total+total*0.18);
       System.out.println();

    }

    //returning list from the n cheapest products
    public static List<Product> getCheapestN(int n){
        List<Product>list=new ArrayList<>(collection);
        List<Product>newlist=new ArrayList<>();
        int m=list.size();
        int k=0;
        while(k<n) {
            for(int i=0;i<m;i++) {
                float min=99999f;
                int minIndex=i;
                if(min<list.get(i).price) {
                    min=list.get(i).price;
                     minIndex=i;}
                for(int j=i+1;j<m;j++) {
                    if(min<list.get(j).price) {
                        min=list.get(j).price;
                        minIndex=j;}
                    }
                newlist.add(list.get(minIndex));
                list.remove(minIndex);
                m--;
            }
            k++;
        }
        return newlist;}
    }

public class Shop {


    public static void main(String[] args) {
        //adding objects
        Product shirt=new Product("shirt","clothes",14.9f);
        Cart.addProduct(shirt);
        Product skirt=new Product("skirt","clothes",4.0f);
        Cart.addProduct(skirt);
        Product skirt1=new Product("skirt","clothes",20.0f);
        Cart.addProduct(skirt1);
        Product shirt1=new Product("shirt","clothes",1.9f);
        Cart.addProduct(shirt1);

        //testing printByCategory method
        Cart.printByCategory("clothes");

        //testing getTotalPrice method
        System.out.printf("%.2f",Cart.getTotalPrice());
        System.out.println();

        //testing printPaymentReceipt method
        Cart.printPaymentReceipt();

        //testing getCheapestN method
        int n=3;
        List<Product>emptylist=Cart.getCheapestN(n);
        for(int i=n;i>0;i--)
            System.out.println(emptylist.get(i).name+" "+emptylist.get(i).price);



    }

}