OrderOfProducts

import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Scanner;

public class _10_OrderOfProducts {

    public static void main(String[] args) throws Exception {
        Locale.setDefault(Locale.ROOT);
        ArrayList<Product> products = new ArrayList<Product>();
        try (Scanner input = new Scanner(new FileReader("Products.txt"))) {
            while (input.hasNextLine()) {
                products.add(new Product(input.next(), input.nextDouble()));
            }
        }
        double result = 0;
        try (Scanner input = new Scanner(new FileReader("Order.txt"))) {
            while (input.hasNextLine()) {
                double quantity = input.nextDouble();
                String currentProduct = input.next();
                for (Product product : products) {
                    if (product.getName().equals(currentProduct)) {
                        result += quantity * product.getPrice();
                    }
                }
            }
        }
        try (BufferedWriter output = new BufferedWriter(new FileWriter("Output.txt"))) {
            output.write(String.format("%.2f", result));
        }
    }
}